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Infección por toxoplasma: panorama actual

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Tema y alcance: este artículo pretende ofrecer al lector una mirada general sobre la toxoplasmosis, una zoonosis causada por Toxoplasma gondii, que afecta tanto a los hospederos intermediarios, como a los definitivos; buscamos que pueda entenderse la dinámica de la enfermedad, dejando de lado ciertos mitos sobre esta. Características: los félidos (Felidae) son los hospederos definitivos, entre los cuales encontramos a los gatos como los más cercanos al ser humano, que desarrollan la forma sexuada del parásito, arrojando al medio los ooquistes infectivos; de allí que su presencia es esencial en el ciclo biológico de T. gondii. Hallazgos: las investigaciones sobre gatos a nivel mundial son limitadas ya que existe una alta complejidad en la toma de muestra; sin embargo, se dispone de un amplia variedad de estudios sobre la taxonomía, morfología, ciclo de vida y biología molecular, así como sobre la distribución epidemiológica, sus hospederos, las vías de transmisión, las fuentes de contaminación y los factores de riesgo asociados con la infección dentro de esta especie y hacia otras vulnerables. Conclusiones: el conocimiento acerca de esta parasitosis es de gran importancia, sobre todo en los casos de mujeres embarazadas y personas inmunodeprimidas, en quienes se puede manifestar complicaciones de la enfermedad.

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... Los parásitos gastrointestinales de caninos y felinos pueden generar enfermedades en los humanos como Larva Migrans Cutánea u Ocular (LMC, LMO), o alteraciones gastrointestinales en niños y adultos (2,5,6). La brucelosis canina, leptospirosis y toxoplasmosis cursan de forma subclínica, inespecífica o agudas tanto en animales como en el hombre, llegando a generar en éste último cuadros clínicos severos (7,8,9,10). Las mascotas son los principales mediadores de contaminación en zonas de esparcimiento familiar por medio de las excretas, por contacto con secreciones animales o por contaminación de alimentos (6,10). ...
... Entre el 50-60% de las mujeres embarazadas en Colombia presentan anticuerpos antitoxoplasma (9), lo que indica una alta circulación del agente en el medio; por sus condiciones tropicales, se considera la toxoplasmosis en Colombia una enfermedad vigente y de serias repercusiones sobre las mujeres gestantes y los neonatos (9,13). Existe un riesgo potencial de que los felinos con elevados títulos de anticuerpos (≥1:320) puedan en algún momento salir del periodo de latencia e iniciar la eliminación de quistes de T. gondii, considerándose esta es una de las muchas causas de transmisión y lo que explicaría los altos porcentajes de mujeres seropositivas al agente (9,26). ...
... Entre el 50-60% de las mujeres embarazadas en Colombia presentan anticuerpos antitoxoplasma (9), lo que indica una alta circulación del agente en el medio; por sus condiciones tropicales, se considera la toxoplasmosis en Colombia una enfermedad vigente y de serias repercusiones sobre las mujeres gestantes y los neonatos (9,13). Existe un riesgo potencial de que los felinos con elevados títulos de anticuerpos (≥1:320) puedan en algún momento salir del periodo de latencia e iniciar la eliminación de quistes de T. gondii, considerándose esta es una de las muchas causas de transmisión y lo que explicaría los altos porcentajes de mujeres seropositivas al agente (9,26). Aunque el felino es el hospedero definitivo, en el cual se desarrolla el ciclo sexual del parásito (9,13); se debe tener presente que las formas de transmisión al humano no requieren del contacto directo con éste (9). ...
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Objetivo. Determinar la prevalencia de agentes zoonóticos en caninos y felinos en Medellín, Colombia. Materiales y métodos. Se muestrearon 1501 individuos para el análisis de parásitos gastrointestinales zoonóticos por medio de coprología directa y flotación. Se examinaron 500 sueros caninos por medio de PARP-2ME y MAT para el diagnóstico de Brucella canis y Leptospira sp, respectivamente. Se procesaron 500 sueros felinos por medio de IFI para el diagnóstico de Toxoplasma gondii. Se estableció la frecuencia para cada zoonosis y la significancia estadística para las diferentes variables (p≤0.05; OR≥1; IC 95%). Resultados. El 23.6% de los caninos y 16.3% de los felinos fueron positivos a parásitos gastrointestinales, siendo los Ancylostomideos y D. caninum los más prevalente, respectivamente; la especie, edad, sexo, sector, estrato socioeconómico y el mes de muestreo presentaron asociaciones con el parasitismo gastrointestinal en mascotas. En caninos se evidenció una seroprevalencia del 6.6% para B. canis y 8.4% para Leptospira sp; en felinos del 56.2% para T. gondii. Todas las anteriores asociadas con la zona de muestreo, mes, edad y estrato. Conclusiones. Las mascotas ubicadas en diferentes comunas y estratos socioeconómicos con condiciones de calidad de vida menores representan un riesgo de transmisión zoonótica.
... En las Américas, los países con mayor prevalencia son San Cristóbal y Nieves (85 %), los Estados Unidos (74 %) y Puerto Rico (70 %). (5,6) En Cuba, en la provincia La Habana, se encontró una seroprevalencia de 70 %, sin diferencias significativas entre zonas y municipios, a pesar de que Habana Vieja, Marianao, San Miguel de Padrón y Regla, fueron los municipios de localización central con mayor prevalencia (80 a 88 %) y Guanabacoa fue el municipio con menor valor (48 %). La prevalencia de Toxoplasma gondii en el resto de los municipios varió entre 54 a 76 %. (7) Los datos publicados demuestran la distribución mundial del germen y la elevada prevalencia de gatos infectados, factor que puede servir de espejo de infestaciones en la población humana. ...
... La mayor endemicidad se asocia a las áreas rurales. (3,6,20,37,38,39,40) Estudios realizados demuestran que no existen diferencias estadísticamente significativas entre tener gatos u otro animal doméstico en la infección por Toxoplasma gondii, lo cual está dado por la transmisión horizontal interespecies. (41,42,43) ...
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Toxoplasmosis has been considered the 20th century parasitic disease, with a seroprevalence of 25-30% of the world human population, and 50%-75% in Cuba. Despite the large number of cases, Toxoplasma gondii is not well known by the general population or even the medical personnel, a fact of which Cuba is not an exception. The objectives of the study were to biologically characterize Toxoplasma gondii and the immune response displayed, and identify the elements facilitating the clinical diagnosis of toxoplasmosis. Toxoplasma gondii may probably infect all warm-blooded animals, including humans. Four different clonal lineages have been described, as well as three main stages in the transmission to definitive and intermediate hosts, cats being the main transmission agents of the infection. Oral and placental transmission are the main routes of transmission of Toxoplasma gondii. Th1 cell response creates a resistance factor in the host. When reduced, the parasite recovers its pathogenicity and may cause disseminated disease. The main groups at risk of contracting the disease are immunocompromised individuals, due to their vulnerability to opportunistic infections. In immunocompetent individuals the primary infection is generally self-limited. The risk factors most commonly cited are close contact with animals and poor hygiene. Despite the availability of satisfactory therapies, prophylactic measures continue to be the main pillar of the treatment of toxoplasmosis. Although the biology of the parasite grants it pathogenicity, a competent immune system and adequate control measures may limit the infection.
... En las Américas, los países con mayor prevalencia son San Cristóbal y Nieves (85 %), los Estados Unidos (74 %) y Puerto Rico (70 %). (5,6) En Cuba, en la provincia La Habana, se encontró una seroprevalencia de 70 %, sin diferencias significativas entre zonas y municipios, a pesar de que Habana Vieja, Marianao, San Miguel de Padrón y Regla, fueron los municipios de localización central con mayor prevalencia (80 a 88 %) y Guanabacoa fue el municipio con menor valor (48 %). La prevalencia de Toxoplasma gondii en el resto de los municipios varió entre 54 a 76 %. (7) Los datos publicados demuestran la distribución mundial del germen y la elevada prevalencia de gatos infectados, factor que puede servir de espejo de infestaciones en la población humana. ...
... La mayor endemicidad se asocia a las áreas rurales. (3,6,20,37,38,39,40) Estudios realizados demuestran que no existen diferencias estadísticamente significativas entre tener gatos u otro animal doméstico en la infección por Toxoplasma gondii, lo cual está dado por la transmisión horizontal interespecies. (41,42,43) ...
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Revista Cubana de Investigaciones Biomédicas. 2019;38(4):e256 Esta obra está bajo una licencia https://creativecommons.org/licenses/by-nc/4.0/deed.es_ES 1 Artículo de revisión El nexo entre biología, respuesta inmune y clínica en la infección por Toxoplasma gondii Relationship between biology, immune response and clinical characteristics in Toxoplasma gondii infection Mileydis Cruz Quevedo 1* RESUMEN La toxoplasmosis ha sido considerada la parasitosis del siglo XX, con una seroprevalencia entre 25-30 % de la población humana general; en Cuba puede oscilar entre 50 %-75 %. A pesar de la casuística, Toxoplasma gondii no es bien conocido por la población general, inclusive por el personal médico; Cuba no escapa de esta realidad. Los objetivos del trabajo son caracterizar biológicamente a Toxoplasma gondii y la respuesta inmune desplegada, e identificar los elementos que facilitan el diagnóstico clínico de la toxoplasmosis. La Toxoplasma gondii puede infectar probablemente a todos los animales de sangre caliente incluyendo los humanos. Se han descrito cuatro linajes clonales diferentes y posee tres estadios principales de transmisión a los hospederos definitivos e intermediarios, siendo el gato el agente principal agente transmisor de la infección. Las transmisiones oral y placentaria son las principales vías de transmisión de Toxoplasma gondii. La respuesta celular Th1 origina un factor de resistencia en el hospedador, al decaer el parásito recupera su patogenicidad y puede ocasionar enfermedad diseminada. Los principales grupos en riesgo a padecer la enfermedad son los individuos inmunodeprimidos en quienes es capaz
... Human factors such as personal hygiene, sanitary conditions, feeding habits, drinking water quality and management practices in livestock production systems can also affect infection rates. 4 Many wild animal species are susceptible to be infected by T. gondii. In fact, several studies have identified high infection rates in zoo animals and wild birds. ...
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El objetivo del presente estudio fue detectar ADN de Toxoplasma gondii en muestras de músculo esquelético y de riñón recolectados de pequeños roedores silvestres, capturados en 10 localidades de la península de Yucatán, México (estados de Campeche, Quintana Roo y Yucatán) en 2018-2019. Se capturaron 127 roedores pertenecientes a siete especies. A todos ellos se les tomó un fragmento de músculo esquelético y de riñón para la extracción de ADN genómico. La identificación de T. gondii se realizó por medio de PCR anidada dirigida a un fragmento del gen B1 del parásito. La especie de roedor con el mayor número de individuos capturados fue Heteromys gaumeri (n=39). La PCR no identificó ADN de T. gondii en los órganos evaluados.
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Congenital toxoplasmosis can cause miscarriage and neurological and/or eye damage to the fetus. Since Austria and France established the prenatal screening, the prevalence of toxoplasmosis has declined from 50% to 35% and 84% to 44%, respectively. Other countries, such as the United Kingdom, have educational practices to reduce the risk of infection in seronegative pregnant women. In Brazil, prenatal screening is carried out in the states of Mato Grosso do Sul and Minas Gerais and the cities of Curitiba and Porto Alegre. In Londrina, state of Parana, the "Health Surveillance Program for Toxoplasmosis Acquired during Pregnancy and Congenital Toxoplasmosis" was established, which is based on serological screening, advising on prevention measures and quarterly serological monitoring in pregnant women that are initially seronegative, in addition to the monitoring of pregnant women and children with acute infection and case notification. In the first four years of implementation, the program evaluation showed a 63% reduction in the number of pregnant women and 42% in the number of children referred to reference services, resulting in the opening of vacancies for the care of patients with other diseases. As for medications, there was a 62% reduction in consumption of folic acid and 67% of sulfadiazine. Moreover, the definition of the protocols resulted in the standardization of care and safety for the decision-making by physicians. Therefore, as there are several protocols individualized in various departments and regions, the establishment of an ideal, consensual conduct with technical support, will result in implementing measures that will certainly save public resources, with the decrease in congenital toxoplasmosis.
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To determine the incidence of congenital toxoplasmosis in Colombian newborns from 19 hospital or maternal child health services from seven different cities of five natural geographic regions (Caribbean, Central, Andean, Amazonia and Eastern). We collected 15,333 samples from umbilical cord blood between the period of March 2009 to May 2010 in 19 different hospitals and maternal-child health services from seven different cities. We applied an IgM ELISA assay (Vircell, Spain) to determine the frequency of IgM anti Toxoplasma. The results in blood cord samples were confirmed either by western blot and repeated ELISA IgM assay. In a sub-sample of 1,613 children that were negative by the anti-Toxoplasma IgM assay, the frequency of specific anti-Toxoplasma IgA by the ISAGA assay was determined. All children with positive samples by IgM, IgA, clinical diagnosis or treatment during pregnancy were recalled for confirmatory tests after day 10 of life. 61 positive samples for specific IgM (0.39%) and 9 positives for IgA (0.5%) were found. 143 questionnaires were positive for a clinical diagnosis or treatment for toxoplasmosis during pregnancy. 109 out of the 218 children that had some of the criteria for postnatal confirmatory tests were followed. Congenital toxoplasmosis infection was confirmed in 15 children: 7 were symptomatic, and three of them died before the first month of life (20% of lethality). A significant correlation was found between a high incidence of markers for congenital toxoplasmosis and higher mean annual rainfall for the city. Incidence for congenital toxoplasmosis is significantly different between hospitals or maternal child health services from different cities in Colombia. Mean annual rainfall was correlated with incidence of congenital toxoplasmosis.
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Congenital toxoplasmosis is a particular manifestation of Toxoplasma gondii infection, which may present as a mild or severe neonatal disease. This pathology remains a difficult challenge in terms of therapy for the pediatrician and gynecologist. In this article we have set ourselves the objective to provide an overview of the main aspects of the disease, with particular attention to the treatment, based on the information in the literature. Two kinds of treatment are currently available: prenatal and postnatal. When pregnant women seroconvert, spiramycin is administered in order to prevent the mother-to-child transmission. When the fetal infection is confirmed the association of pyrimethamine and sulfadiazine is prescribed. After birth the specific therapy is based on the administration of pyrimethamine and sulfadiazine. However, to date, there is not strong evidence on the effectiveness of treatment, whether prenatal or postnatal. The studies undertaken so far have not given satisfactory answers. Double-blind randomized controlled trials would be required, but for obvious ethical reasons they cannot be achieved.
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Cats are important in the epidemiology of Toxoplasma gondii because they are the only hosts that excrete environmentally resistant oocysts in feces. In the present study, 158 feral cats from Giza, Egypt, were examined for T. gondii infection. Antibodies to T. gondii were found in 97.4% with the modified agglutination test. Viable T. gondii was isolated from tissues (brain, heart, tongue) of 115 of 137 cats by bioassay in mice. These isolates were designated TgCatEg 1-115; none of these isolates was virulent to out-bred Swiss Webster mice. Of the 112 seropositive cats whose tissues were bioassayed individually, T. gondii was isolated from the hearts of 83 (74.1%), tongues of 53 (47.3%), and brains of 36 (32.1%). Toxoplasma gondii oocysts were not detected in rectal contents of any of the 158 cats, probably related to high seropositivity (chronic infection) of cats surveyed. The high prevalence of T. gondii in feral cats in Egypt reported here indicates a high environmental contamination with oocysts.
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The principal objective of this study was to investigate the prevalence of toxoplasmosis in household and stray cats in Seoul, Republic of Korea. We collected blood samples from 72 stray and 80 household cats, and all samples were examined by ELISA and nested PCR. The overall positive rates of Toxoplasma gondii in stray cats were 38.9% (28/72), with 15.3% (11/72) in ELISA and 30.6% (22/72) in PCR. The positive rate in male stray cats was slightly higher than that of female stray cats. The highest positive rate of T. gondii infection was noted in Gangnam and Songpa populations in ELISA and in Gwangjin population in PCR. In household cats, however, we could not detect any specific antibodies or DNA for T. gondii. In conclusion, we recognized that the infection rate of toxoplasmosis in stray cats in Seoul was considerably high but household cats were free from infection.
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This 2e of Toxoplasma gondii reflects the significant advances in the field in the last 5 years, including new information on the genomics, epigenomics and proteomics of T. gondii as well as a new understanding of the population biology and genetic diversity of this organism. T. gondii remains the best model system for studying the entire Apicomplexa group of protozoans, which includes Malaria, making this new edition essential for a broad group of researchers and scientists. Toxoplasmosis is caused by a one-celled protozoan parasite known as T. gondii. The infection produces a wide range of clinical syndromes in humans, land and sea mammals, and various bird species. Most humans contract toxoplasmosis by eating contaminated, raw or undercooked meat (particularly pork), vegetables, or milk products; by coming into contact with the T. gondii eggs from cat feces; or by drinking contaminated water. The parasite damages the ocular and central nervous systems, causing behavioral and personality alterations as well as fatal necrotizing encephalitis. It is especially dangerous for the fetus of an infected pregnant woman and for individuals with compromised immune systems, such as HIV-infected patients.
Article
The present reflection was aimed at making a contribution towards improving control policy and programs integrality and efficacy in an attempt to answer the following question, “How can understanding zoonoses in Colombia be approached from a complexity-based approach?” The first part of this article examines zoonoses as a complex problem and the reiterated tendency of control policy and programs to deal with them as a simple problem, involving unidisciplinary and reductionist responses. The current status of complexity is synthesized as a paradigm, as are the advantages of using it in analysis and formulating policy and interventions. Possible fields of work are proposed for development when approaching zoonoses in Colombia from a complexity science viewpoint.
Article
Toxoplasmosis is a parasitic zoonosis having worldwide distribution; it infects many human and animal populations and is produced by the parasite Toxoplasma gondii, this being of great importance in contagion of pregnant women since this zoonosis causes illness in the fetus through transplacental infection. A constant mother-foetus infection rate has traditionally been used. Nevertheless, there is evidence of a strong relationship between a mother's gestation week and the moment when a foetus becomes infected. This work describes congenital toxoplasmosis transmission dynamics by using an age-structured model taking a mother's gestational week into account. The model was adapted to a space-time model describing T. gondii dispersion through cats; this provided the amount of parasites in the environment depending on which a pregnant woman would become infected. Simulations were done, varying the amount of parasites and the pregnant mother-inoculum distance. Some parameters related to possible control measures were also varied. Important changes were found when comparing infected pregnant female population patterns, when a constant mother-fetus infection rate was used and when a dependent pregnancy week rate was used. This led to concluding that the gestation week in which the mothers became infected is fundamental in infection being transmitted to their fetuses.
Article
Toxoplasma gondii es el agente causal de la toxoplasmosis, zoonosis reemergente y cosmopolita, que afecta a hospederos intermediarios y definitivos. El gato domestico es el hospedero definitivo mas cercano al ser humano que desarrolla la forma sexuada del parasito y es el productor de ooquistes, de alli que su presencia es esencial en el ciclo biologico de T. gondii. Las investigaciones en el gato a nivel mundial son escasas debido principalmente a la complejidad en la toma de muestra; sin embargo, se dispone de conocimientos sobre la taxonomia, morfologia, ciclo biologico y biologia molecular, asi como, sobre la distribucion geografica, sus hospederos, la resistencia al ambiente, las vias de transmision, fuentes de contaminacion y factores de riesgo asociados con la infeccion dentro de esta especie y hacia otras vulnerables. Ademas, se han realizado trabajos para comprender la patogenia, manifestaciones clinicas, lesiones anatomopatologicas, inmunidad, diagnostico y control de este agente biologico.
Article
Blood sample and placenta were taken from a 37weeks pregnant woman; serologic results indicated acute toxoplasmosis. Placenta was inoculated into mice. Seropositive mice were sacrificed and tissue cysts from brain were inoculated into new mice. Specific DNA was detected by PCR, and the isolate was characterized as Type II by nPCR-RFLP for nSAG2, SAG3, BTUB, GRA6, c29-2, c22-8, L358, PK1 and Apico markers. This is the first isolation and molecular characterization of Toxoplasma gondii from humans from Argentina.
Article
The prevalence of chronic Toxoplasma infections reported in the literature varies enormously. We hypothesize that one factor could be due to the different methods used in the evaluation of infections. Serological evidence of Toxoplasma infections in 450 pregnant women (PW) and 300 HIV-infected patients (HIV) were investigated by the Sabin-Feldman Dye test and two other commercial ELISA kits (kit1 and kit2). Anti-Toxoplasma IgG antibodies obtained from the Sabin-Feldman Dye test, ELISA kit1 and ELISA kit2 in the PW subjects were 14.7%, 29.6% and 38.7%, and in the HIV subjects were 13%, 34.7% and 36.3% respectively. So there were significant differences in the seroprevalences when different diagnostic tests were used (P < 0.05). Regarding Sabin-Feldman Dye test as the gold standard for anti-Toxoplasma antibodies detection, we found that the sensitivity and specificity of the ELISA kit1 and kit2 was in the range of their specification. However as the two ELISA kits used in our study identified a much higher prevalence of Toxoplasma infections which indicated that false positive cases were being reported. Based on results obtained, it is therefore highly recommended that research workers should be aware that the reports of serological studies in terms of high positive results should be treated with some skepticism until additional precise diagnostic tools are developed.
Article
The apicomplexan parasite Toxoplasma gondii was discovered a little over one hundred years ago and was soon recognized as a pathogen responsible for congenital infection. But detailed understanding of its epidemiology emerged only after 1970 with the discovery of its life cycle. In the last ten years, high resolution molecular tools have allowed the characterization of various strain types with different virulence patterns, and current studies are exploring the distribution of these different genotypes. In parallel, sophisticated diagnostic tools have been developed and awareness of disease burden has led some European countries with high prevalence rates to implement screening of pregnant women. In this article, the screening options and therapies used to prevent congenital toxoplasmosis are dissected in the light of recent data from cohort studies and other epidemiological data.
Article
La toxoplasmosis es una infección parasitaria cosmopolita que afecta a entre un tercio y un cuarto de la población mundial. Las fuentes de contaminación múltiples (carne, agua, tierra, verduras) explican la adquisición a menudo precoz de la infección en el transcurso de la vida. La infección adquirida suele ser benigna y asintomática, aunque puede producir linfadenopatías. En Francia, por ejemplo, la toxoplasmosis congénita adquirida tras la infección materna durante el embarazo afecta a alrededor de 300 niños cada año. Al nacer, más del 80% de ellos no tiene signos clínicos, pero alrededor de un 25% desarrolla coriorretinitis. Las formas graves de toxoplasmosis congénita, neurooculares o diseminadas, son infrecuentes en Francia. Las lesiones oculares, sean adquiridas o congénitas, son más graves y más precoces en otros países, sobre todo de América del Sur, debido a la presencia de cepas más virulentas. Ante la ausencia frecuente de signos clínicos, el diagnóstico de la toxoplasmosis congénita se basa en pruebas biológicas efectuadas en laboratorios especializados. En un niño cuya madre sufrió una seroconversión durante el embarazo, sólo la desaparición completa de las inmunoglobulinas G (IgG), anticuerpos antitoxoplásmicos, permite descartar el diagnóstico de toxoplasmosis congénita. La conducta actual consiste en tratar al recién nacido durante el primer año de vida con una asociación de sulfadiazina-pirimetamina o de sulfadoxina-pirimetamina. Este tratamiento no está exento de toxicidad y su eficacia no ha sido demostrada. Las lesiones oculares pueden aparecer o recidivar bajo tratamiento. Es fundamental, por tanto, prevenir la toxoplasmosis congénita, sobre todo ofreciendo consejos de higiene a las mujeres embarazadas seronegativas.
Article
In Tunisia, despite the absence of a national program of congenital toxoplasmosis prevention, serodiagnosis is regularly carried out in pregnant women for prenatal screening. We report our experience on congenital toxoplasmosis over the last 11 years (2000–2011). Methods We reviewed the clinical, biological and therapeutic features of 21 cases of congenital toxoplasmosis. Results The infection occurred in the first trimester in four cases, in the second trimester in six cases and in the third trimester in four cases. Presumed date of maternal contamination could not be specified in seven cases. Spiramycin was prescribed in 16 cases and pyrimethamine-sulfadiazine in one case with a positive PCR. Fetal ultrasound was poorly contributive in the antenatal screening. It showed intra-uterine growth retardation in one case. At birth, 16 neonates were asymptomatic, four presented neurological symptoms and four presented ocular involvement. The postnatal serology was positive for 21 neonates during the first month of life. IgA were positive in 76.9 % of cases and IgM in 66.6 % of cases. Comparison of immunoblot profiles showed a neo-synthesis of IgG and/or IgM in 57.1 % of cases. Twenty neonates were treated with sulfadoxine-pyrimethamine. The evolution was marked by the early death of two neonates. Conclusion Severe congenital toxoplasmosis is still relevant in our country. The management of pregnant women at risk needs to be improved.
Article
This review examines parasite zoonoses and wildlife in the context of the One Health triad that encompasses humans, domestic animals, wildlife and the changing ecosystems in which they live. Human (anthropogenic) activities influence the flow of all parasite infections within the One Health triad and the nature and impact of resulting spillover events are examined. Examples of spillover from wildlife to humans and/or domestic animals, and vice versa, are discussed, as well as emerging issues, particularly the need for parasite surveillance of wildlife populations. Emphasis is given to Trypanosoma cruzi and related species in Australian wildlife, Trichinella, Echinococcus, Giardia, Baylisascaris, Toxoplasma and Leishmania.
Article
Ocular infestation with Toxoplasma gondii, a parasite, may result in inflammation in the retina, choroid, and uvea and consequently lead to complications such as glaucoma, cataract, and posterior synechiae. The objective of this systematic review was to assess the effects of adjunctive use of corticosteroids for ocular toxoplasmosis. We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 9), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE, (January 1950 to October 2012), EMBASE (January 1980 to October 2012), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to October 2012), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We searched the reference lists of included studies for any additional studies not identified by the electronic searches. We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 11 October 2012. We planned to include randomized and quasi-randomized controlled trials. Eligible trials would have enrolled participants of any age who were immunocompetent and were diagnosed with active ocular toxoplasmosis. Included trials would have compared anti-parasitic therapy plus corticosteroids versus anti-parasitic therapy alone, or different doses or times of initiation of corticosteroids. Two authors independently screened titles and abstracts retrieved from the electronic searches. We retrieved full-text articles of studies categorized as 'unsure' or 'include' after review of the abstracts. Two authors independently reviewed each full-text article. Discrepancies were resolved through discussion. The electronic searches retrieved 368 titles and abstracts. We reviewed 20 full-text articles. We identified no trials eligible for inclusion in this systematic review. Although research has identified wide variation in practices regarding use of corticosteroids, our systematic review did not identify evidence from randomized controlled trials for the role of corticosteroids in the management of ocular toxoplasmosis. Several questions remain unanswered by well-conducted randomized trials in this context, including whether use of corticosteroids is more effective than use of anti-parasitic therapy alone, when corticosteroids should be initiated in the treatment regimen (early versus late course of treatment), and which dosage and duration of steroid use is best. These questions are easily amenable to research using a randomized controlled design and they are ethical due to the absence of evidence to support or discourage use of corticosteroids for this condition. The question of foremost importance, however, is whether they should be used as adjunct therapy (that is, additional) to anti-parasitic agents.
Article
Congenital toxoplasmosis is considered a rare but potentially severe infection. Prenatal education about congenital toxoplasmosis could be the most efficient and least harmful intervention, yet its effectiveness is uncertain. To assess the effects of prenatal education for preventing congenital toxoplasmosis. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (15 January 2012), PubMed (1966 to 15 January 2012), EMBASE (1980 to 15 January 2012), CINAHL (1982 to 15 January 2012), LILACS (1982 to 15 January 2012), IMEMR (1984 to 15 January 2012), and reference lists of relevant papers, reviews and websites. Randomized and quasi-randomized controlled trials (RCTs) of all types of prenatal education on toxoplasmosis infection during pregnancy. Cluster-randomized trials were included. Two review authors independently assessed trials for inclusion and study quality. Two review authors extracted data. Data were checked for accuracy. Two cluster-randomized controlled trials (involving a total of 5455 women) met the inclusion criteria. The two included trials measured the effectiveness of the intervention in different ways which meant that meta-analysis of the results was not possible One trial (432 women enrolled) conducted in Canada was judged of low methodological quality. The authors did not report measure of association but only provided P values (P less than 0.05) for all outcomes. Moreover, losses to follow-up were high (34%, 147 out of 432 women initially enrolled). The authors concluded that prenatal education can effectively change pregnant women's behavior as it increased pet, personal and food hygiene. The second trial conducted in France was also judged of low methodological quality. Losses to follow-up were high (44.5%, 2233 out of 5023 women initially enrolled) and differential (40% in the intervention group and 52% in the control group). The authors concluded that prenatal education for congenital toxoplasmoses has a significant effect on improving women's knowledge whereas it has no effect on changing women's behavior. In this trial 17/3949 pregnant women seroconverted for toxoplasmosis: 13/2591 (0.5%) in the intervention group and 4/1358 (0.3%) in the control group. The number of events was too small to reach conclusions about the effect of prenatal education on seroconversion rate during pregnancy.No other randomized trials on the effect of prenatal education on congenital toxoplasmosis rate, or toxoplasmosis seroconversion rate during pregnancy were detected. Even though primary prevention of congenital toxoplasmosis is considered a desirable intervention, given the lack of related risks compared to secondary and tertiary prevention, its effectiveness has not been adequately evaluated. There is very little evidence from RCTs that prenatal education is effective in reducing congenital toxoplasmosis even though evidence from observational studies suggests it is. Given the lack of good evidence supporting prenatal education for congenital toxoplasmosis prevention, further RCTs are needed to confirm any potential benefits and to further quantify the impact of different sets of educational intervention.
Article
The objectives of this study were to analyze the association between the classification of toxoplasmosis in the pregnant woman (TP) according to the classification of Lebech et al. and the incidence of congenital toxoplasmosis (CT), also taking into consideration prenatal treatment. A clinical cohort study of 524 children followed-up until 1 year of age was conducted. Adjusted odds ratios (OR) were estimated by logistic regression. Of 519 pregnant women, 61.3% were not classified due to the incompleteness of hospital records. Among the pregnant women classified as confirmed cases of TP (n=19), the CT risk was six times greater than in the probable/possible group. No case of CT was identified in the group of pregnant women classified as unlikely to have TP. The children with no prenatal treatment (46.2% n=242/524) presented a risk almost three times greater of CT than the treated children (OR 2.77, 95% confidence interval (CI) 1.54-4.97; p=0.001). Complete prenatal treatment was identified as a protecting factor for CT (OR 0.35, 95% CI 0.19-0.65; p=0.001). A lack or incomplete prenatal treatment was identified as an important risk factor for CT in this study. The proportions of non-classified mothers and children with no prenatal treatment reflect the need to improve prenatal care in Brazil.
Article
Cats are essential in the epidemiology of Toxoplasma gondii because they are the only hosts that can excrete the environmentally resistant oocysts in nature. This study was aimed to determine the seropositivity, distribution of genotypes and mouse virulence of T. gondii from stray cats in Beijing, China. A total of 64 serum samples, 23 feces and tissue samples were collected from stray cats in Beijing. Antibodies to T. gondii were assayed by the modified agglutination test (MAT). 57.8% (37/64) of these stray cats had titers of 1:20 or higher and were considered positive with infection. T. gondii oocysts were not found in feces of the 23 cats. Tissues of 23 cats were bioassayed in mice and 11 T. gondii isolates were obtained. The genotype of these isolates were identified by 11 PCR-RFLP markers, including SAG1, (3'+5')SAG2, alt.SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and an apicoplast marker, Apico. Only one genotype was identified. This genotype, designated as ToxoDB genotype #9, was previously reported in cats, pigs and human from Guangdong and Gansu provinces in China and animals from a few other countries. To determine mouse virulence of this lineage of parasites, one isolate was randomly selected and inoculated into BABL/c mice, the result showed that it is intermediately virulent to mice. These results indicated that an atypical, intermediately virulent T. gondii lineage is widespread in China. The high seropositivity of T. gondii in stray cats posts potential risk of transmission of the parasite to human population in the region.
Article
Cats, as definitive hosts, play an important role in the transmission of Toxoplasma gondii. To determine the seroprevalence and risk factors for T. gondii infection in Dutch domestic cats, serum samples of 450 cats were tested for T. gondii antibodies by indirect ELISA. Binary mixture analysis was used to estimate the seroprevalence, the optimal cut-off value and the probability of being positive for each cat. The seroprevalence was estimated at 18.2% (95% CI: 16.6-20.0%) and showed a decrease with age in very young cats, an increase up to about 4 years old and ranged between 20 and 30% thereafter. Hunting (OR 4.1), presence of a dog in the household (OR 2.1), former stray cat (OR 3.3) and feeding of raw meat (OR 2.7) were identified as risk factors by multivariable logistic regression analysis. Prevalence differences were estimated by linear regression on the probabilities of being positive and used to calculate the population attributable fractions for each risk factor. Hunting contributed most to the T. gondii seroprevalence in the sampled population (35%).
Article
Systemic infections, such as toxoplasmosis, acquired during pregnancy can lead to placental infection and have profound effects on the mother-to-child relationship and the success of pregnancy. Placental permeability to Toxoplasma gondii is a main parameter that determines parasite transmission to the foetus, and the use of antibiotics to decrease placental parasite load and prevent congenital toxoplasmosis has been suggested for decades. Although parasitological examination of the placenta at birth is commonly used to diagnose neonatal congenital toxoplasmosis, this approach can be controversial. Here we argue in favour of placental examination for both diagnostic and epidemiological purposes.
Article
Toxoplasmosis is a rare disease caused by the obligate intracellular protozoan parasite, Toxoplasma gondii. Most persons with toxoplasmosis in the United States are asymptomatic, but if a woman is infected during pregnancy, the parasite can cross the placenta and cause congenital toxoplasmosis in the fetus. The severity of congenital toxoplasmosis depends on when in the pregnancy the mother is exposed, but it can cause ocular and central nervous system disease as well as lead to growth failure and hearing and vision abnormalities. Congenital toxoplasmosis is treated with a combination of pyrimethamine, sulfadiazine, and leucovorin. It is important for pediatric nurse practitioners to be aware of the clinical presentation and treatment of congenital toxoplasmosis.
Article
Toxoplasma gondii (T. gondii) is a unicellular protozoan that infects up to one-third of the world's human population. Numerous studies revealed that a latent infection of T. gondii can cause life-threatening encephalitis in immunocompromised people and also has significant effects on the behavior of healthy people and animals. However, the overall transmission of T. gondii has not been well understood although many factors affecting this process have been found out by different biologists separately. Here we synthesize what is currently known about the natural history of T. gondii by developing a prototype agent-based model to mimic the transmission process of T. gondii in a farm system. The present model takes into account the complete life cycle of T. gondii, which includes the transitions of the parasite from cats to environment through feces, from contaminated environment to mice through oocysts, from mice to cats through tissue cysts, from environment to cats through oocysts as well as the vertical transmission among mice. Although the current model does not explicitly include humans and other end-receivers, the effect of the transition to end-receivers is estimated by a developed infection risk index. The current model can also be extended to include human activities and thus be used to investigate the influences of human management on disease control.
Article
Felines are the key species in the epidemiology of Toxoplasma gondii infection, as they are the definitive host of the parasite and are the only species that can shed resistant oocysts in the environment. Different assays are in use for the detection of antibodies against T. gondii in cats. However, assay validation studies are limited. For that reason it was our aim to first evaluate 6 serological tests (one commercial and 2 in-house ELISAs, ImmunoComb, IFAT and MAT) for antibodies (IgG) against T. gondii in cats by Bayesian modeling. Factors associated with seropositivity were evaluated by bivariable and multivariable methods. The test evaluation indicated the commercial ELISA had the highest Youden Index. The estimated sensitivity ranged between 95.7% and 97.1% and the specificity between 97.3% and 97.6%. Using this commercial ELISA 111 out of 236 cats (47%) were positive for T. gondii antibodies. Two peaks in the percentage of strong positive samples (S/P≥200) were observed, around 10-months-old and 8-years-old. In bivariable analysis the seroprevalence was significantly higher in adult cats, cats with mixed diet, with outdoor access, in cats from a rural area and in cats from centre and north-western Romania. Adult age (adults: OR 6.98; 95% CI: 2.02-24.14 and geriatrics (cats older than 10-years): OR 12.01; 95% CI: 1.60-90.15) and outdoor access (OR 6.38; 95% CI: 2.32-17.53) remained significant risk factors in the multivariable logistic regression analysis. Our results suggest that T. gondii infection is common in household cats in Romania, and especially in those with outdoor access.
Article
The presence of cats in the farms is considered a risk factor for the infection of pigs with Toxoplasma gondii (T. gondii). Cats eliminate oocysts that contaminate food, water and promote the infection of host reservoir such as rodents and birds among others that are also involved in the infection of pigs. The objective of this study was to assess the dynamic of infection of T. gondii in seronegative weaned pigs from weaning to 20 weeks of age from two farms from an endemic region, one with high and low density of cats. A cohort study was performed in 64 pigs, 31 newly weaned pigs on a farm with a high density of cats (FA) and 33 newly-weaned pigs on a farm with a low density of cats (FB). Blood samples were collected every 14 days to determine the presence of IgG antibodies against T. gondii in the serum using an indirect ELISA test. True incidence rate (TIV), cumulative incidence (AI) and relative risk (RR) was calculated. The age of seroconversion was determined by using survival tables; both farms were compared with Long-Rank test. In FA 97.5% of the pigs seroconverted at the second sampling and 100% at the third sampling, while in the FB all pigs seroconverted to the fourth sampling. The TIV was 0.67 and 0.43 for FA and FB respectively, during the first four weeks at risk. A RR of 1.5 (1.04-2.39) was obtained (p<0.05). Animals of the FA had a higher risk of infection compared with the FB, however, all animals included in the study had contact with the agent. Infection with T. gondii was rapidly distributed in both farms, regardless of the relative density of cats observed during the study. These results suggest a high environmental contamination with oocysts in the facilities of both farms probably due to the fact that T. gondii infection is endemic in the area where the farms are located, allow proper establishment of the etiological agent. The points of prevention and control strategies to avoid exposure of pigs to T. gondii in an endemic area should focus on the control of cats and rodents.
Article
Toxoplasma gondii is a parasite of birds and mammals. Cats are the only definitive host and thus the only source of infective oocysts, but other mammals and birds can develop tissue cysts. Although feline infections are typically asymptomatic, infection during human pregnancy can cause severe disease in the fetus. Cat owners can reduce their pets' exposure risk by keeping all cats indoors and not feeding them raw meat. Humans usually become infected through ingestion of oocyst-contaminated soil and water, tissue cysts in undercooked meat, or congenitally. Because of their fastidious nature, the passing of non-infective oocysts, and the short duration of oocyst shedding, direct contact with cats is not thought to be a primary risk for human infection.
Article
A total of 18,259 feline faecal samples from cats in Germany were collected and analysed for the presence of Toxoplasma gondii oocysts between June 2007 and December 2008. The proportion of T. gondii-positive samples collected between January and June was significantly lower than between July and December. The age of cats shedding T. gondii oocysts was not significantly different from the age of negative control cats. Forty-six T. gondii-positive samples were genetically characterised using nine PCR-restriction fragment length polymorphism (RFLP) markers which included newSAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and Apico. In addition, 22 isolates that had already been partially characterised in a previous study were further typed using PCR-RFLP markers c22-8, c29-2, L358, PK1 and Apico. Genotyping of the 68 isolates revealed that the majority of T. gondii isolates (n=54) had Type II patterns at all loci but displayed a Type I pattern at the Apico locus. Three isolates displayed Type II patterns at all loci, including the Apico locus. In addition, we detected one isolate with clonal Type III patterns at all loci and three isolates with atypical and mixed genotypes. Seven isolates could not be fully genotyped. One of those isolates displayed alleles of both Types I and II at the Apico locus. To our knowledge this is the first description of the presence of T. gondii genotypes different from the clonal Types I, II and III in the faeces of naturally infected cats.
Article
Humans become infected with Toxoplasma gondii mainly by ingesting uncooked meat containing viable tissue cysts or by ingesting food or water contaminated with oocysts from the feces of infected cats. Circumstantial evidence suggests that oocyst-induced infections in humans are clinically more severe than tissue cyst-acquired infections. Until recently, waterborne transmission of T. gondii was considered uncommon, but a large human outbreak linked to contamination of a municipal water reservoir in Canada by wild felids and the widespread infection of marine mammals in the USA provided reasons to question this view. The present paper examines the possible importance of T. gondii transmission by water.
Article
One-third of the human world population is infected with the protozoan parasite Toxoplasma gondii. Recent calculations of the disease burden of toxoplasmosis rank this foodborne disease at the same level as salmonellosis or campylobacteriosis. The high disease burden in combination with disappointing results of the currently available treatment options have led to a plea for more effective prevention. In this review we describe Toxoplasma as a hazard associated with the consumption of undercooked meat or meat products and provide an analysis of the various options to control the risk of human toxoplasmosis via this source. Monitoring and surveillance programs may be implemented for pre-harvest control of Toxoplasma infection of farm animals, with the reduction of environmental oocyst load as the most important milestone. Alternatively, Toxoplasma safe meat can be obtained through simple post-harvest decontamination procedures, whereby freezing the meat may currently be the best option, although new technologies using irradiation or high-pressure treatment may offer promising alternatives. Influence of culture, religion and food handling customs may predispose a certain type of meat as an important source of infection, indicating that prevention needs to be tailored according to social habits in different regions in the world. The rationale for more stringent control measures to prevent toxoplasmosis both from disease and economic points of view is emphasized.
Article
Coccidian oocysts resembling those of Isospora bigemina were excreted by cats fed Toxoplasma. In order to identify these oocysts with Toxoplasma infectivity a number of critical comparisons were made. The appearance of oocysts and Toxoplasma infectivity was simultaneous in the feces of 23 of 24 adult cats, 3-5 days after feeding of Toxoplasma cysts; in the feces of 4 out of 9 cats, 7-10 days after feeding of trophozoites; and in 8 out of 17 cats, 20-24 days after feeding of cat feces containing oocysts. Oocysts and infectivity were present in similar numbers, and they disappeared simultaneously from the feces of cats. Oocysts and infectivity were also observed simultaneously in the feces of 9 kittens, 1-2 days old, fed Toxoplasma cysts. Oocysts could not be separated from infectivity by filtration, by continuous particle electrophoresis, or by density gradient centrifugation. Excystation of oocysts was followed by an increase in titer of Toxoplasma infectivity. Unsporulated oocysts in fresh cat feces were noninfectious to mice, but oocyst sporulation was associated quantitatively with the development of infectivity at different temperatures and conditions of oxygenation. Maximum oocyst sporulation at 48 hr correlated with the development of maximum Toxoplasma infectivity. 1 and 2% sulfuric acid, and 2.5% potassium dichromate were found to be the best preservatives for sporulation of oocysts and for the development of Toxoplasma infectivity. Low sporulation rates in 0.1% formalin, 20% ethanol, and in water were associated with low infectivity in these reagents. Neither Toxoplasma infectivity nor oocysts developed in 0.3% formalin, 1% ammonium hydroxide, or 1% iodine in 20% ethanol. Oocysts, sporocysts, and sporozoites were stained specifically with Toxoplasma antibody in the indirect fluorescent antibody test. Typical coccidian stages, schizonts, and male and female gametocytes were found in the epithelium of the small intestine of kittens fed Toxoplasma cysts. The classification of T. gondii is discussed in relation to that of other isosporan coccidia of cats and dogs. The term "Toxoplasma oocyst" is introduced and Toxoplasma is classified in the family Toxoplasmidae of the suborder Eimeriina. The species Isospora bigemina is restricted to dogs, and I. cati to cats. I. felis and so-called I. rivolta from cats were noninfectious to dogs, and did not confer immunity to subsequent infection with I. canis and I. rivolta from dogs.
Article
Toxoplasmosis is a widespread parasitic disease and usually causes no symptoms. However, infection of pregnant women may cause congenital infection, resulting potentially in mental retardation and blindness in the infant. The objective of this review was to assess whether or not treating toxoplasmosis in pregnancy reduces the risk of congenital toxoplasma infection and improves infant outcomes. The Cochrane Pregnancy and Childbirth Group trials register was searched. An electronic search was performed using the key words 'congenital and toxoplasmosis' on the following databases: MEDLINE (1966-07/1997), Embase (1993-07/1997), Pascal (French) (1990-1997), Biological Abstracts (1993-1995) and the Cochrane Controlled Trials Register. There was also contact with experts in the field, including those in the European Research Network on Congenital Toxoplasmosis. Randomised controlled trials of antibiotic treatment versus no treatment of pregnant women with proven or likely acute Toxoplasma infection, with outcomes in the children reported. We also inspected relevant reports of less robust experimental studies in which there were (non randomly allocated) control groups, although it was not planned to include such data in the primary analysis. Reports of possibly eligible studies were scrutinised by two investigators. Out of the 2591 papers identified, none met the inclusion criteria. Despite the large number of studies performed over the last three decades we still do not know whether antenatal treatment in women with presumed toxoplasmosis reduces the congenital transmission of Toxoplasma gondii. Screening is expensive, so we need to evaluate the effects of treatment, and the impact of screening programmes. In countries where screening or treatment is not routine, these technologies should not be introduced outside the context of a carefully controlled trial.
Article
This paper reviews clinical and asymptomatic Toxoplasma gondii infection in humans and other animals in the USA. Seroprevalence of T. gondii in humans and pigs is declining. Modes of transmission, epidemiology and environmental contamination with oocysts on land and sea are discussed.
The performance of four molecular methods for the laboratory diagnosis of congenital toxoplasmosis in amniotic fluid samples
  • Le Teixeira
  • Ka Kanunfre
  • Pt Shimokawa
  • Ls Targa
  • Jc Rodriguez
  • W Domingues
Teixeira LE, Kanunfre KA, Shimokawa PT, Targa LS, Rodriguez JC, Domingues W. The performance of four molecular methods for the laboratory diagnosis of congenital toxoplasmosis in amniotic fluid samples. Rev Soc Bras Med Trop. 2013;46(5):584-8.
Oocyst shedding in cats vaccinated by the nasal and rectal routes with crude rhoptry proteins of Toxoplasma gondii
  • D L Zulpo
  • S A Headley
  • L Biazzono
  • Da Cunha
  • I A Igarashi
  • De Barrios
Zulpo DL, Headley SA, Biazzono L, Da Cunha IA, Igarashi M, De Barrios LD, et al. Oocyst shedding in cats vaccinated by the nasal and rectal routes with crude rhoptry proteins of Toxoplasma gondii. Exp Parasitol. 2012;131(2):223-30.
Validación de un sistema inmunoenzimático de inhibición para el diagnóstico de Toxoplasma gondii en Felis catus
  • R Grandía Guzmán
  • Entrena García
  • Cruz Hernández
  • Ginorio Gavito
  • Domenech Cañete
  • Alfonso Morales
Grandía Guzmán R, Entrena García AA, Cruz Hernández J, Ginorio Gavito N, Domenech Cañete I, Alfonso Morales A, et al. Validación de un sistema inmunoenzimático de inhibición para el diagnóstico de Toxoplasma gondii en Felis catus. Rev Electrón Vet. 2013;14(7):1-12.
Toxoplasmosis ganglionar Presentación atípica en un niño inmunocompetente: reporte de caso
  • S N González
  • P M Macías
  • T V Gómez
  • M I Zuyino
González SN, Macías PM, Gómez TV, Zuyino MI. Toxoplasmosis ganglionar Presentación atípica en un niño inmunocompetente: reporte de caso. Pediatr Infect Dis J. 2012;25:99.
Antibiotics versus control for toxoplasma retinochoroiditis. Cochrane Database of Systematic Reviews
  • R E Gilbert
  • M Harden
  • M Stanford
Gilbert RE, Harden M, Stanford M. Antibiotics versus control for toxoplasma retinochoroiditis. Cochrane Database of Systematic Reviews. 2011;Issue 8:1-22.
  • S L Rita
  • C C Martha
  • G G Doris
  • N R Alfredo
  • S R Niobys
  • S G Irina
Rita SL, Martha CC, Doris GG, Alfredo NR, Niobys SR, Irina SG et al. Toxoplasmosis y embarazo. Rev Cub Gin y Obs. 2012;38(1):99-106.
Prenatal education for congenital toxoplasmosis
  • Di Mario
  • S Basevi
  • V Gagliotti
  • C Spettoli
  • D Gori
  • D ' Amico
  • R Magrini
Di Mario S, Basevi V, Gagliotti C, Spettoli D, Gori G, D' Amico R, Magrini N. Prenatal education for congenital toxoplasmosis. Cochrane Database of Systematic Reviews. 2013;(2):1-25.