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Nuevos casos de infección humana por Diphyllobothrium pacificum (Nybelin, 1931) Margolis, 1956 en Chile y su probable relación con el fenómeno de El Niño, 1975-2000
Abstract
The effect of El Niño/ENSO on terrestrial atmosphere appears to be extremelly clear. However there are outstanding evidences showing its effect on humans and their activities. In fact, prevalence of some parasitic infections have increased during El Niño phenomenon. The reasons for that are the migrations of sylvatic mammals, fishes and birds as well as by environmental contamination. In this report, we show evidence respect of new cases of human infection by Diphyllobothrium pacificum clearly associated with a cyclic manifestation of El Niño in the Chilean Pacific coast during 1975-2000
... The majority of human cases have been recorded in Peru; around 1,000 cases have been detected since 1950 (Kuchta et al., 2015a). In Chile and Ecuador, 19 (Sagua et al., 2001;Mercado et al., 2010) and 13 cases (Gallegos and Brousselle, 1991) have been reported, respectively. Also, 5, 6, and 10 cases have been reported in Spain, Japan, and Russia, respectively (Kuchta et al., 2015a). ...
... Although the frequency of plerocercoids in salmon muscles reached between 15.6 and 20.0%, their potential risk of transmission to humans through the consumption of dishes based on raw or insufficiently cooked fish would be scarce since the mean of plerocercoids/infected salmon did not exceed 0.4 parasites/infected salmon. The latter and the lack of records of muscular infection in marine fish off South America would explain, in part, the low reported number of human cases in Chile (Sagua et al., 2001;Mercado et al., 2010). In some countries the consumption of salted fish eggs or raw liver could be a potential source of human infection due to diphyllobothriids (Kuchta et al., 2015b). ...
Adenocephalus pacificus (Cestoda: Diphyllobothriidae) is a fish foodborne zoonotic parasite whose stage of plerocercoid has been identified in marine fish. The objective of this study is to report for first time the infection by A. cf. pacificus in the anadromous Coho salmon, Oncorhynchus kisutch, from the Simpson River, Chile. During July 1997 and July 1998, the fish were examined for diphyllobothriidean parasites. The plerocercoids were found encysted in the stomach, peritoneum, liver, spleen, gonads, and muscles. The prevalence of infection fluctuated between 75.0 and 100% and the mean intensity was between 31.6 ± 25.4 and 34.9 ± 27.9 plerocercoids in July 1997 and July 1998, respectively. The frequency of plerocercoids in the muscles was 15.6 to 20.0%, respectively, and the mean was 0.3–0.4 plerocercoids/infected fish. Eight adult dogs were submitted to fecal exams and treated with a broad-spectrum antiparasitic. Six of 8 dogs were successfully orally infected by freshly obtained plerocercoids. Two of them ingested 40 plerocercoids, and we recovered between 34 and 32 cestodes at 21 and 27 d postinfection (DPI), respectively; we identified only 3 gravid specimens in the last dog and the rest of the worms were nongravid. The other dogs presented between 1 and 4 cestodes at 29 and 44 DPI. The prepatent period fluctuated between 21 and 28 DPI and the gravid cestodes measured between 24 and 104 cm long. Morphological identification of the studied adults was confirmed by light and scanning electron microscopy.
... En Chile, la infestación con plerocercoides de Diphyllobothrium ha sido también detectada en el salmón coho (Oncorhynchus kisutch) 29 , una especie de salmonídeos introducida al país y que vive en el ambiente silvestre como resultado de haber escapado de jaulas mantenidas en el mar, en el proceso de su crianza industrial 3,25,30 . Larvas plerocercoides de otra tenia del pescado, D. pacificum, cuyo huésped definitivo son mamíferos marinos como las focas y los lobos marinos, también han sido detectados en la carne de otros peces chilenos y han producido algunos casos de difilobotriasis en el norte del país 31,32 . Es bien sabido que las jaulas de acuicultura en el mar atraen a estos mamíferos y esto crearía la posibilidad de instaurar el ciclo biológico de este difilobotrio alternativo alrededor de estas jaulas 31,32 . ...
... Larvas plerocercoides de otra tenia del pescado, D. pacificum, cuyo huésped definitivo son mamíferos marinos como las focas y los lobos marinos, también han sido detectados en la carne de otros peces chilenos y han producido algunos casos de difilobotriasis en el norte del país 31,32 . Es bien sabido que las jaulas de acuicultura en el mar atraen a estos mamíferos y esto crearía la posibilidad de instaurar el ciclo biológico de este difilobotrio alternativo alrededor de estas jaulas 31,32 . Pero este escenario parece ser poco probable para explicar las infestaciones por Diphyllobothrium en Brasil ya que los parásitos diagnosticados en ese país tenían las característi-cas morfológicas de D. latum, que es el parásito humano endémico en los lagos de las regiones IX y X 9,15-24 y la presencia de D. pacificum no ha sido aún descrita en los mares del sur de Chile. ...
Recent clinical and epidemiológica! information, an analysis of the literature, and study of the technical aspects of Chilean salmon aquaculture indicate that this activity has the ability to expand the range of diphyllobothriasis caused by the fish tapeworm Diphyllobothrium latum. Evidence for expansion of the range of the fish tapeworm includes the emergences of clinical cases in Brazil related to consumption of salmon produced in Chile. Expansion of the range of this parasite is also suggested by an increase of its geographical range in Chile, beyond its previously endemic foci in the lakes of Regions IX and X. Prevention of further dissemination of this parasitic disease rests on an improvement of sanitation and sewage disposal around the lakes of Regions IX, X and XI in Chile, improvement in aquaculture methods including curtailing the use offish tapeworm-contaminated lakes to grow juveniles forms ofsalmonids and more measures to decrease the number of salmonid escapees from marine pens to prevent their return to rivers and lakes carrying the infestation. Moreover, tracking the origin ofjuveniies in marketed salmon, determining the presence of plerocercoids in them, and increased education of the public regarding the potential dangers of eating raw fish should also be implemented. Only by stimulating the dialogue between the industry, consumers and state regulators will it be possible to implement appropriate measures to prevent further expansion of this parasitic disease by salmon aquaculture (Rev Méd Chile 2007; 135:1064-71)
... Most human infections caused by D. pacificum and, allegedly, D. latum have been reported from Chile and Peru, with other cases in Argentina, Brazil, and Ecuador (17,18,39,40,54,(145)(146)(147), including recent outbreaks of diphyllobothriosis in Rio de Janeiro and São Paulo (46,47,153). ...
... Seemingly unrelated environmental changes may also have unexpected effects on the epidemiology of this zoonosis. It has been suggested that the increase in human infections with D. pacificum in northern Chile during the period of 1975 to 2000 was related to the cyclic appearance of El Niño phenomena in the Eastern Pacific, which affected not only fish populations but also the primary definitive host of this tapeworm, the sea lion (145). ...
Tapeworms (Cestoda) continue to be an important cause of morbidity in humans worldwide. Diphyllobothriosis, a human disease caused by tapeworms of the genus Diphyllobothrium, is the most important fish-borne zoonosis caused by a cestode parasite. Up to 20 million humans are estimated to be infected worldwide. Besides humans, definitive hosts of Diphyllobothrium include piscivorous birds and mammals, which represent a significant zoonotic reservoir. The second intermediate hosts include both freshwater and marine fish, especially anadromous species such as salmonids. The zoonosis occurs most commonly in countries where the consumption of raw or marinated fish is a frequent practice. Due to the increasing popularity of dishes utilizing uncooked fish, numerous cases of human infections have appeared recently, even in the most developed countries. As many as 14 valid species of Diphyllobothrium can cause human diphyllobothriosis, with D. latum and D. nihonkaiense being the most important pathogens. In this paper, all taxa from humans reported are reviewed, with brief information on their life history and their current distribution. Data on diagnostics, epidemiology, clinical relevance, and control of the disease are also summarized. The importance of reliable identification of human-infecting species with molecular tools (sequences of mitochondrial genes) as well as the necessity of epidemiological studies aimed at determining the sources of infections are pointed out.
... Human diphyllobothriasis has been reported in Europe, Asia, North America, and South America. South American has reported cases from Peru, Chile, and Argentina, but not Brazil (2)(3)(4)(5)(6)(7). South American diphyllobothriasis is an ancient disease; D. pacificum eggs were found in coprolites, 4,000-to 5,000-year-old Chinchorro Chilean mummies (8). ...
... Four recognized species, D. latum, D. pacificum, D. klebanovskii, and D. nihonkaiense, infect humans; many species infect fish-eating birds, dogs, foxes, and bears (2,5). Species identification is relevant because D. pacificum infects only saltwater fish. ...
Cases of human diphyllobothriasis have been reported worldwide. Only 1 case in Brazil was diagnosed by our institution from January 1998 to December 2003. By comparison, 18 cases were diagnosed from March 2004 to January 2005. All patients who became infected ate raw fish in sushi or sashimi.
... In Chile, infestation with Diphyllobothrium plerocercoids has also been detected in coho salmon living in the wild, a nonindigenous species raised originally in aquaculture that escaped from pens (19). Larvae of another fish tapeworm, D. pacificum, whose definitive hosts are large marine mammals such as sea lions and fur seals, have been detected in marine fish in Chile (20). Salmon aquaculture sea cages attracts these large mammals, creating the possibility for the parasite life cycle to occur in the environment around the salmon cages (20). ...
... Larvae of another fish tapeworm, D. pacificum, whose definitive hosts are large marine mammals such as sea lions and fur seals, have been detected in marine fish in Chile (20). Salmon aquaculture sea cages attracts these large mammals, creating the possibility for the parasite life cycle to occur in the environment around the salmon cages (20). However, this is an unlikely scenario for the spread to human populations, because the fish tapeworms identified in the patients in Brazil had the morphologic characteristics of D. latum, which as discussed above is one of the diphyllobothrium endemic in the lakes of southern Chile (5-9). ...
... Respecto a estas condiciones, debe señalarse que los contagios de parásitos normalmente ocurren por consumo de alimentos infectados, agua y por el ciclo «ano-mano-boca, lo que facilita que una persona se contagie a si mismo» (Geosalud 2004); como también a su grupo, sin requerir otros vectores. Asimismo, aspectos culturales como el proceso de agriculturización y su concomitante sedentarismo (Larsen 1995: 198) produjo significativas modificaciones en los hábitos alimenticios (Sagua et al. 2000(Sagua et al. , 2001, sanitarios (Morales et al. 1999) y de higiene de las poblaciones prehispánicas, que facilitaron el desarrollo de las enfermedades parasitarias. ...
... Se encontraron los estadios infectantes de A. pacificus, A. simplex, Contracaecum sp. y C. obtuscens, los cuales presentan importancia zoonótica en la costa peruana (Tantaleán, 1975(Tantaleán, , 1993(Tantaleán, , 1994Sagua et al., 2000Sagua et al., , 2001Tantaleán & Michaud, 2005: Luque et al., 2016Gómez del Prado-Rosas et al., 2017). El hallazgo de las formas infectivas de anisákidos y diphillobothrideos en el pez investigado muestra que esta especie de hospedero tiene una alta capacidad zoonótica en la costa central peruana. ...
Este trabajo presenta un avance de investigación interdisciplinaria que desarrolla perspectivas teóricas, analíticas e interpretativas, para el estudio situado de la alimentación, salud, nutrición y la cultura, en Latinoamérica, particularmente en el puerto y ciudad turística de Mazatlán, Sinaloa, México. Las miradas teóricas y las rutas metodológicas parten de considerar que, además de los evidentes aportes nutricionales, los alimentos son portadores de significados, entendidos éstos como atributos conferidos culturalmente. La revisión bibliográfica identificó una variedad de especies de patógenos potencialmente zoonóticos, transmitidos por peces en hospedadores acuáticos que son comunes en comunidades costeras del mundo, destacando la importancia del consumo de pescado crudo en la transmisión de parásitos y posible zoonosis con afección al humano. Asimismo, se expone críticamente la visión antropológica de la alimentación con respecto a las identidades sociales y turismo gastronómico, enfatizando la experiencia compartidas por países latinoamericanos costeros y turísticos como Perú, Chile y México, respecto al consumo de alimentos marinos no cocidos como ostiones y el ceviche. Además, se analizan las dificultades de diagnóstico de infecciones humanas con helmintos como nematodos y cestodos transmitidos por peces al ser humano, y se discuten los requisitos para un enfoque integrado para evitar la infección, concluyendo que; a) la nematodiosis y cestodiasis transmitida por peces humanos puede constituir un problema de salud pública en dichas comunidades; b) se deben adoptar regulaciones efectivas para prevenir la infección; c) las personas deben abstenerse de comer platos de pescado crudos o poco cocidos; d) se debe emprender una campaña intensiva para alertar a las personas sobre las conductas de riesgo de alimentación.
... Respecto a estas condiciones, debe señalarse que los contagios de parásitos normalmente ocurren por consumo de alimentos infectados, agua y por el ciclo «ano-mano-boca, lo que facilita que una persona se contagie a si mismo» (Geosalud 2004); como también a su grupo, sin requerir otros vectores. Asimismo, aspectos culturales como el proceso de agriculturización y su concomitante sedentarismo (Larsen 1995: 198) produjo significativas modificaciones en los hábitos alimenticios (Sagua et al. 2000(Sagua et al. , 2001, sanitarios (Morales et al. 1999) y de higiene de las poblaciones prehispánicas, que facilitaron el desarrollo de las enfermedades parasitarias. ...
... Eggs of this species (morphologically diagnosed) were found in coprolites from 2,700 to 2,850 BC in a coastal site in North-Central Peru (Reinhard and Urban, 2003) and at the site of Tiliviche in Northern Chile from 4,110-1,950 BC (Ferreira et al., 1984). Human infections have been reported with about 1,000 (Flores et al., 2002;Kuchta et al., 2015b), 19 (Sagua et al., 2001;Mercado et al., 2010), and 13 (Gallegos and Brousselle, 1991) human cases from Peru, Chile and Ecuador, respectively. Also, Kuchta et al. (2015b) mentioned a case of a student from Peru who was in Argentina and was infected with a tapeworm identified as Lueheella sp. ...
... It is possible that climatic changes could favour D. latum life cycle by warming freshwater systems, thus increasing the percentage of infected fish (Patz et al. 2000;Marcogliese 2001;Sagua et al. 2001). This should also be investigated by future regular monitoring of endemic lakes located in endemic areas. ...
In recent years, human diphyllobothriosis has staged a comeback in Swiss, French and Italian sub-alpine regions. The main putative infective source of the causative agent (the tapeworm Diphyllobothrium latum) in these areas is perch (Perca fluviatilis). Therefore, the occurrence of D. latum in this fish species was investigated between 2005 and 2008 in the sub-alpine lakes Maggiore, Lugano and Geneva. Prevalence in fish of Lake Maggiore was 14% (n = 880). In Lake Geneva, 5.1% fillets (n = 532) were infected, whereas perch from Lake Lugano were free from the parasite. These results are discussed in relation to previous studies. Data on fish size and weight indicate that infection of perch by D. latum is independent of age and sex. Abiotic factors considered critical for D. latum life cycle (water temperature and oxygen concentration) characterize the three basins and were related to their infestation frequencies. The presence of this parasite was most likely favoured by warmer, well oxygenated waters. Previous studies indicate that the lake's trophic state (i.e. content of total phosphorus) influenced the availability of the first intermediate hosts (copepods) of some pseudophyllideans. In our study, no correlation was observed between the amount of phosphorus and the number of copepods in populations of zooplankton. Nevertheless, the trophic states of the three lakes seemed to affect the degree of infection in fish. In conclusion, at least in sub-alpine lakes, abiotic factors such as water temperature, oxygenation and trophic state seem to have an influence on maintaining or preventing perch infection with D. latum.
The nematode parasites Anisakis spp., Pseudoterranova spp., and Contracaecum spp., all within the family Anisakidae, and cestode parasites within the genus Diphyllobothrium are present in marine ecosystems with life cycles that often involve invertebrate and fish intermediate hosts and marine mammal definitive hosts. Human infections with these parasites have been recorded and are thought to be associated with traditional practices of consuming uncooked fish. Sensitivities and allergic reactions to nematode antigens have also been reported in humans with continued contact with fish (e.g., fish plant workers). There are concerns about the emergence and re-emergence of these zoonoses as a food safety issue associated with changes in the availability of food sources and in species distributions of intermediate hosts related to climate change.
The oceanographic conditions of the Pacific Ocean are largely modified by El Niño (EN), affecting several ecological processes. Parasites and other marine organisms respond to environmental variation, but the influence of the EN cycle on the seasonal variation of parasitic copepods has not been yet evaluated. We analysed the relation between infection parameters (prevalence and mean intensity) of the widespread parasitic copepods Caligus bonito and Charopinopsis quaternia in the dolphinfish Coryphaena hippurus and oceanography during the strong 2015–16 EN. Fish were collected from capture fisheries on the Ecuadorian coast (Tropical Eastern Pacific) over a 2-year period. Variations of sea surface temperature (SST), salinity, chlorophyll a (Chl-a), Oceanic Niño Index (ONI), total host length (TL) and monthly infection parameters of both copepod species were analysed using time series and cross-correlations. We used the generalised additive models for determine the relationship between environmental variables and infection parameters. The total body length of the ovigerous females and the length of the eggs of C. bonito were measured in both periods. Infection parameters of both C. bonito and Ch. quaternia showed seasonal and annual patterns associated with the variation of environmental variables examined (SST, salinity, Chl-a and ONI 1+2). Infection parameters of both copepod species were significantly correlated with ONI 1+2, SST, TL and Chl-a throughout the GAMLSS model, and the explained deviance contribution ranged from 16%-36%. Our results suggest than an anomaly higher than +0.5°C triggers a risen in infection parameters of both parasitic copepods. This risen could be related to increases in egg length, female numbers and the total length of the ovigerous females in EN period. This study provides the first evidence showing that tropical parasitic copepods are sensitive to the influence of EN event, especially from SST variations. The observed behaviour of parasitic copepods likely affects the host populations and structure of the marine ecosystem at different scales.
The prevalence, mean intensity, mean abundance, and mean density of infection by helminths, myxozoans, and rnicrosporidians were determined in the muscles of southern hake, Merluccius australis (n = 104), pink cusk-eel, Genypterus blacodes (n =81), and snoek, Thyrsites atun (n = 95), all of them sold fresh in the city of Valdivia, Chile. Fish were examined on a candling table, with direct observation of the dorsal and ventral muscles (candling 1), in cuts 4 mm thick or less (candling 2), and on a glass plate compression. Prevalence, mean intensity, and mean abundance of infection, by all the identified parasites in each host, were significantly higher (P <0.05) in hake and pink cusk-eel, compared with the snoek. Mean density of infection in the hake was higher (P <0.05) than in pink cusk-eel; the latter had a higher (P <0.05) density of infection than the snoek. All fish hosts showed parasites with potential risks to human health, such as Anisakis sp. types I and II or Pseudoterranova sp. Other parasites were also detected in each fish host: metacercariae of trematodes, Hepatoxylon trichiuri, Pseudoterranova sp., Anisakis sp. type I, Kudoa sp., and microsporidians in the hake; metacercariae of trematodes, Pseudoterranova sp., Anisakis 'sp. types I and type II, Corynosoma sp., Kudoa sp., and microsporidians in pink cusk-eel; and Molicola sp., Pseudoterranova sp., and Anisakis sp. type I in the snoek. Pseudoterranova sp. and Molicola sp. had the highest prevalence, mean intensity, mean abundance, and mean density of infection in the pink cush-eel and the snoek, respectively. In the hake, the highest prevalence, mean abundance and mean density were determined for Kudoa sp; mean intensity of infection was highest for microsporidiosis.
Technical Appendix. Historical survey of records of adult Adenocephalus
pacificus, marine fish reported as second intermediate hosts of A. pacificus, and descriptions of clinical cases of diphyllobothriosis caused by A. pacificus.
In Chile, infection by Anisakid nematodes has been reported in humans associated with raw ("cebiche") and smoked marine fishes consumption. During 1994, 125 fresh marine fishes commercialized in markets from Valdivia, Chile, were microscopically examined for anisakids in the musculature. From the 10 species examined the following fish species were infected (n o of infected/examined fishes) with Anisakis simplex (As), Pseudoterranova decipiens (Pd) and Hysterothylacium sp. (H sp.): the Chilean hake, Merluccius gayi (As 1/ 17; Pd 4/17), the tail-hake, Macrouronus magellanicus (Pd 1/4; H sp. 1/4), the red-conger-eel, Genypterus chilensis (Pd 9/18), the flat-fish, Paralichthys microps (As 1/10; Pd 7/10) and the Chilean mackerel, Trachurus murphyi (As 2/16; Pd 5/16). All isolated anisakid larvae were alive. The highest number of anisakid per fish (4 larvae) was detected in M. gayi and T. murphyi but the highest density, 3.3 worms/100 g of muscles, was observed in P. microps. The number of parasites was scarce, but their presence in the commercialized fishes in Valdivia, without freezing or sanitary inspection represents a potential risk.
The Pacific broad tapeworm Adenocephalus pacificus (syn. Diphyllobothrium pacificum) is the causative agent of the third most common fish-borne cestodosis among humans. Although most of the nearly 1,000 cases among humans have been reported in South America (Peru, Chile, and Ecuador), cases recently imported to Europe demonstrate the potential for spread of this tapeworm throughout the world as a result of global trade of fresh or chilled marine fish and travel or migration of humans. We provide a comprehensive survey of human cases of infection with this zoonotic parasite, summarize the history of this re-emerging disease, and identify marine fish species that may serve as a source of human infection when eaten raw or undercooked. © 2015, Centers for Disease Control and Prevention (CDC). All rights reserved.
La prevalencia e intensidad, abundancia y densidad media de infección por helmintos, myxozoos y microsporidios fue determinada en músculos de merluza austral, Merluccius australis (n= 104), congrio dorado, Genypterus blacodes (n = 81) y sierra, Thyrsites atun (n = 95), comercializados frescos en la ciudad de Valdivia, Chile. El análisis fue realizado en mesa de candling, observando directamente la musculatura dorsal y ventral (candling 1), en cortes de 4 mm o menos de espesor (candling 2) y por compresión en placas. La prevalencia, intensidad media y abundancia media de infección, por el total de parásitos determinados en cada huésped, resultaron significativamente mayores (P < 0,05) en la merluza y el congrio, respecto a la sierra. La densidad media fue significativamente mayor (P < 0,05) en la merluza respecto al congrio y en este último resultó mayor (P < 0,05) que en la sierra. Las tres especies de peces presentaron parásitos de riesgo potencial para la salud humana, como Anisakis sp. tipos I y II o Pseudoterranova sp. Los siguientes parásitos fueron determinados en cada huésped: metacercarias de trematodos, Hepatoxylon trichiuri, Pseudoterranova sp., Anisakis sp. tipo I, Kudoa sp. y microsporidios no identificados en merluza; metacercarias, Pseudoterranova sp., Anisakis sp. tipos I y II, Corynosoma sp., Kudoa sp. y microsporidios no identificados en el congrio; y Pseudoterranova sp., Anisakis sp. tipo I y Molicola sp. en la sierra. La mayor prevalencia e intensidad, abundancia y densidad media de infección fue para Pseudoterranova sp. y Molicola sp. en congrio y sierra, respectivamente. La mayor prevalencia, abundancia y densidad media de infección en merluzas correspondió a Kudoa sp., y la mayor intensidad de infección fue observada para la microsporidiosis.
In this communication is presented the finding of the tapeworm Diphyllobothrium pacificum, parasite of sea lions, in Canis familiaris (dog) in Chincha city, Peru. This is the first canine infection with D. pacificum in the South Peruvian coast
In Chile, infection by Anisakid nematodes has been reported in humans associated with raw ("cebiche") and smoked marine fishes consumption. During 1994, 125 fresh marine fishes commercialized in markets from Valdivia, Chile, were microscopically examined for anisakids in the musculature. From the 10 species examined the following fish species were infected (n of infected/examined fishes) with Anisakis simplex (As), Pseudoterranova decipiens (Pd) and Hysterothylacium sp. (H sp.): the Chilean hake, Merluccius gayi (As 1/17; Pd 4/17), the tail-hake, Macrouronus magellanicus (Pd 1/4; H sp. 1/4), the red-conger-eel, Genypterus chilensis (Pd 9/18), the flat-fish, Paralichthys microps (As 1/10; Pd 7/10) and the Chilean mackerel, Trachurus murphyi (As 2/16; Pd 5/16). All isolated anisakid larvae were alive. The highest number of anisakid per fish (4 larvae) was detected in M. gayi and T. murphyi but the highest density, 3.3 worms/100 g of muscles, was observed in P. microps. The number of parasites was scarce, but their presence in the commercialized fishes in Valdivia, without freezing or sanitary inspection represents a potential risk
Cestodes, or tapeworms, belong to the class Cestoidea of the phylum Platyhelminthes. Members of this family vary greatly in
size and behavior; however, they share the same basic body plan. They attach to the intestinal wall of definitive hosts by
the scolex, or head. The scolex is followed by the neck, behind which grow the body segments, or proglottids. The proglottids
together form the strobila, or body, of the worm; the number of proglottids in the adult worm depends on the species. Proglottids
have both longitudinal and transverse muscles and are motile. Each proglottid also has both male and female reproductive organs,
but mating usually occurs with adjacent segments rather than by self-fertilization. The oldest proglottids are farthest from
the scolex and contain the tapeworm’s eggs. Cestodes have no digestive or circulatory system and must absorb nutrients from
the lumen of the host’s small intestine through microvilli. These cover the surface of each proglottid and excrete waste through
a pair of excretory tubules. Tapeworms do have a rudimentary nervous system consisting of ganglia in the scolex and nerves
in the proglottids.
Diphyllobothriasis caused by the infection of adult Diphyllobothrium tapeworms sporadically occurs in Chile. The occurrence of the disease is closely linked to the consumption of raw or undercooked freshwater and marine fishes. Diagnosis of diphyllobothriasis has been based on laboratory examinations of the morphological characteristics of proglottids and eggs passed in the feces. Although determination of the parasite to the species level is possible through histologic examination of proglottid specimens, the parasites of patients who only discharge eggs cannot be diagnosed to the species level. Determining the species responsible for the infection of humans and other animals in affected areas is an important component of understanding the epidemiologic and enzootic characteristics of any infectious disease. We therefore compared the classification results obtained using a molecular approach with those obtained from morphological and histopathological examination of proglottids or eggs from five Chilean individuals with diphyllobothriasis. DNA analysis confirmed that the causative Diphyllobothrium species in Chile were first identified as Diphyllobothrium latum and Diphyllobothrium pacificum at least. Furthermore, mitochondrial cytochrome c oxidase subunit 1 gene analysis also supported the hypothesis that D. latum from Chile originated from Europe.
In this communication is presented the finding of the tapeworm Diphyllobothrium pacificum, parasite of sea lions, in Canis familiaris (dog) in Chincha city, Peru. This is the first canine infection with D. pacificum in the South Peruvian coast.
From Phoca vitulina richardi the following parasites are recorded: Corynosoma strumosum (Acanthocephala); Terranova decipiens and Contracaecum osculatum (Nematoda); Halarachne sp. (Acarina); Echinophthirius horridus (Anoplura). From Eumetopias jubata are recorded Diphyllobothrium pacificum, Diplogonoporus tetrapterus and Abothrium gadi (Cestoda); T. decipiens, C. osculatum and Parafilaroides sp. (Nematoda); Corynosoma villosum (Acanthocephala); Orthohalarachne diminuata (Acarina): Antarctophthirus microchir (Anoplura). E. jubata is probably not a true host of A. gadi, the parasite apparently being introduced by ingestion of infected fishes of the family Gadidae, the normal definitive hosts. Notes on host and geographical distribution, nomenclature and morphology of the parasites are included. Diphyllobothrium pacificum is a new combination for Adenocephalus pacificus. E. jubata is a new host record for D. pacificum, D. tetrapterus and O. diminuata. Several new geographical records are reported. The occurrence of larval stages of T. decipiens and C. strumosum in fishes is noted.
Applicable publications, involving five languages, have been reviewed to obtain information on El Niños that occurred over the past four and a half centuries. Since this information refers strictly to El Niño occurrences, a regional manifestation of the large-scale (El Niño-Southern Oscillation (ENSO)) event, it is based primarily on evidence obtained from the west coast region of northern South America and its adjacent Pacific Ocean waters. Authored lists of events were not acceptable without referenced valid information sources. It was desirable to have cross-correlated reports from independent sources. Relative strengths of events are based on such considerations as wind and current effects on travel times of ancient sailing ships, degree of physical damage and destruction, amounts of rainfall and flooding, mass mortality of endemic marine organisms and guano birds, extent of invasion by tropical nekton, rises in sea temperatures and sea levels, affects on coastal fisheries and fish meal production, etc. Emphasis is placed on strong and very strong events. For example, the 1940-1941, 1957-1958, and 1972-1973 events fall into the strong category, whereas the 1891, 1925-1926 and 1982-1983 events are considered very strong. Over our period of study, 47 El Niño events were placed in the strong or very strong categories. Over the period 1800-present, we noted 32 El Niño events of moderate or near moderate intensity. Weak events are not included here. The approach used here caused us to revise many of our earlier evaluations concerning event occurrences and intensities. Our tropical Pacific thickness analyses and cumulative plots of Southern Oscillation index anomalies over the southeast Pacific trade wind zone showed additional evidence as to the unusual strength of the 1982-1983 event. Also, in our investigation we noted several periods of long-term (near decadal or longer) climatic change.
Diphyllobothrium pacificum, a tapeworm from seals, is reported for the first time from man in Peru. Seven further cases are described from people living along the coast and whose food includes various species of sea fish. The very complicated history of the parasite which involves numerous synonyms has been established. This is also first report of human diphyllobothriasis other than D. latum from the Southern Hemisphere.
Difilobotriasis humana por Diphyllobothrium pacificum en Chile: Experiencasi con 11 casos
- H. Sagua
- A. Fuentes
- J. Soto
- B. Délano
Diphyllobothrium pacificum (Nybelin, 1931) Margolis, 1956: Primeros dos casos de infección humana en el norte de Chile
- H. Sagua
- E. Miranda
- A. Fuentes
- V. Vladilo
Estado actual de la investigación sobre cestodos del género Diphyllobothrium Cobbold en Chile
- P. Torres
Diphyllobothrium pacificum: Hallazgo de larvas plerocercoides en peces marinos del Perú y desarrollo de formas adultas del parásito en Canis familiaris
- H. Escalante
- H. Miranda
Infección por Diphyllobothrium pacificum, probablemente adquirida en el sur de Chile, por un niño de tres años
- R. Mercado
- P. Torres
- A. Lobos
- H. Schenonoe
Primer caso humano de infección por Diphyllobothrium pacificum en Chile
- A. Atías
- P. Cattan
Nuevos registros de parásitos en mamíferos marinos chilenos
- J. Fernández
Difilobotriasis humana por Diphyllobothrium pacificum.: Un nuevo caso en Antofagasta, Norte de Chile
- A. González
- H. Sagua
- L. Cortés
- J. Lobo
- I. Neira
- J. Araya
Hallazgo de huevos de Diphyllobothrium pacificum en coprolitos humanos del norte de Chile (4100 al 1950 a de C
- L. Nuñez
- L. Fernando
- A. De Araujo