Olga Matos

• Associate Professor with Habilitation of Medical Parasitology
• Professor (Associate) at Universidade NOVA de Lisboa

Cryptosporidium spp. and Giardia duodenalis are important diarrheal agents in children in developing countries. Little is known about their molecular epidemiology; as such, the objective of this study was to determine the risk factors and genetic diversity of both parasites in diarrheal samples in Mozambique. In this study, two nested PCRs targetin...

Cutaneous larva migrans (CLM) is a dermatosis caused by accidental infestation with animal hookworms and is widely distributed in tropical and subtropical regions. Humans become infected when their skin comes into contact with soil contaminated with dog faeces. The filariform larvae penetrate and burrow into human skin, causing a condition known as...

Accurate genomic sequencing demands high-quality double-stranded RNA (dsRNA). Existing methods for dsRNA extraction from yeast, fungi, and plants primarily rely on cellulose, suitable only for small volume extractions, or the time-consuming lithium chloride precipitation. To streamline the traditional phenol-chloroform-based dsRNA extraction method...

Giardia duodenalis and Enterocytozoon bieneusi are etiological agents of enteric diseases characterized by diarrhea that can progress to chronicity in humans, especially in children and in immunocompromised patients. This study aims to assess the genetic pattern of G. duodenalis and E. bieneusi detected in vegetables and fruits commercialized in Ma...

Diarrhea remains a public health problem in Mozambique, even with control strategies being implemented. This analysis aimed to determine the proportion and factors associated with intestinal parasitic infection (IPI) in children up to 14 years old with diarrheal disease, in the southern, central and northern regions of Mozambique. A single diarrhea...

(1) Background: Giardia duodenalis and Cryptosporidium are important neglected parasites associated with diarrhea, such as the emerging Enterocytozoon bieneusi. All three are foodborne parasites raising concerns in public health. This study intended to understand the intestinal parasite occurrence with emphasis on G. duodenalis, Cryptosporidium, an...

The clinical picture of the fungal disease, Pneumocystis pneumonia, resembles the course of coronavirus disease 2019 (COVID-19), presenting a diagnostic challenge in the pandemic era. We discuss the concern of Pneumocystis jirovecii and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) coinfection, their similarities, and the impact of i...

Twenty-years ago, considering the host specificity of Pneumocystis species, the human-derived Pneumocystis, Pneumocystis carinii formae specialis hominis, was renamed Pneumocystis jirovecii. Pneumocystis carinii formae specialis carinii was finally renamed Pneumocystis carinii and kept for the species derived from Rattus norvegicus. P. jirovecii is...

Introdução Desde o início da epidemia da síndrome de imunodeficiência adquirida (sida) que vários microrganismos têm surgido como importantes agentes patogénicos, afetando, em particular, os doentes com sida mas também doentes com outras imunodeficiências. Atualmente, a pneumonia por Pneumocystis jirovecii e a encefalite por Toxoplasma gondii são d...

We describe the prevalence of Pneumocystis jirovecii in mother-infant pairs of very low birth weight newborns <32 weeks gestation. Molecular and microscopic methods were used for detection of P. jirovecii in patients' specimens. Pneumocystis DNA was detected in eight nasopharyngeal aspirates (14%) of 56 newborns and in seven oral washes (21%) of 34...

Environmental health is at the intersection between health and the environment. However, it still has a recent (and narrow) history as a scientific area, mainly addressing human biomonitoring and toxicological issues. Only recently additional environmental ‘layers’, other than the traditional chemical, biological and physical environmental determin...

In developing countries, markets are the main supply of horticultural products to populations, but this can pose a public health challenge due to the risk of the fecal-oral transmission of gut pathogens. This transmission is strongly associated with inadequate public sanitation or low standards of personal and domestic hygiene, and their prevalence...

Interest in the detection of specific anti-Pneumocystis jirovecii antibodies has emerged as less-invasive alternative diagnostic approaches. Here is presented the performance of an ELISA based on a recombinant synthetic multi-epitope kexin 1 (Kex1) antigen of P. jirovecii, previously developed. Results showed that IgM anti-Kex1 levels were found si...

Pneumocystis jirovecii and microsporidia species are recognized as opportunistic infectious pathogens in AIDS patients. Coinfection of both in one patient has been rarely reported. The aim of the present study was to investigate the coinfection of P. jirovecii and microsporidia in different tissues from AIDS deceased patients. Post mortem histologi...

Pneumocystis jirovecii and Microsporidia species are recognized as opportunistic infectious pathogens in AIDS patients. Co-infection of both in one patient has been rarely reported. The aim of the present study was to investigate the co-infection of P. jirovecii and Microsporidia in different tissues from AIDS deceased patients. Post mortem histolo...

Environmental health is at the intersection between health and the environment. However, it still has a recent (and narrow) history as a scientific area, mainly addressing human biomonitoring and toxicological issues. Only recently additional environmental 'layers', other than the traditional chemical, biological and physical environmental determin...

Pneumocystis jirovecii pneumonia (PcP) is a major human immunodeficiency virus (HIV)-related illness, rising among immunocompromised non-HIV patients and in developing countries. Presently, the diagnosis requires respiratory specimens obtained through invasive and costly techniques that are difficult to perform in all patients or implement in all e...

Introduction: Pneumocystis jirovecii pneumonia (PcP) is an important morbidity/mortality factor in immunocompromised patients, whose diagnosis requires respiratory specimens obtained by invasive and costly techniques. Thus, the development of a rapid, cost-effective, minimally invasive and field-friendly test to diagnose PcP would be a significant...

Until now, in Romania, a country in southeastern Europe located on the Balkans Peninsula, information regarding the status on A. mellifera honey bee infection by Nosema spp. has not been published. The aims of the present study were to survey the occurrence and identification of Nosema spp. in A. mellifera honeybee colonies from 37 apiaries located...

Pneumocystis jirovecii is an opportunistic fungus occurring in human lungs. The group at highest risk consists of HIV-infected and non-HIV-infected immunosuppressed individuals. In these patients, P. jirovecii infection may lead to Pneumocystis pneumonia; it may, however, persist also in an asymptomatic form. This study aimed to determine the preva...

Until now, in Romania, a country in southeastern Europe located on the Balkans Peninsula, information regarding the status on A. mellifera honey bee infection by Nosema spp. has not been published. The aims of the present study were to survey the occurrence and identification of Nosema spp. in A. mellifera honeybee colonies from 37 apiaries located...

Pneumocystis jirovecii pneumonia (PcP) remains a major cause of respiratory illness among immunocompromised patients. PcP is difficult to diagnose, in particular in non-HIV-infected patients, due to the lack of associated specific clinical data. Since P. jirovecii could not be cultivated for many years, microscopic visualization of cystic or trophi...

Pneumocystis jirovecii is an opportunistic fungus causing Pneumocystis pneumonia primarily in immunosuppressed patients. However, immunocompetent individuals may become colonized and, as asymptomatic carriers, serve as reservoirs of the pathogen. Moreover, these asymptomatic carriers are at higher risk of developing pneumonia if favorable condition...

Pneumocystis jirovecii pneumonia (PcP or pneumocystosis) remains a major cause of respiratory illness among immunocompromised patients, especially those infected with the human immunodeficiency virus (HIV). P. jirovecii infection has also been detected in healthy individuals and people with chronic lung diseases, raising the possibility that the sp...

To understand the epidemiological significance of Pneumocystis detection in a lung tissue sample of non-immunosuppressed individuals, we examined sampling procedures, laboratory methodology, and patient characteristics of autopsy series reported in the literature. Number of tissue specimens, DNA-extraction procedures, age and underlying diagnosis h...

Clinical and microbiological characteristics of the samples harboring the 201s fungal individuals.

Clinical and microbiological characteristics of the all the 249 patients and samples including mixed amples.

Pneumocystis jirovecii is an airborne human-specific ascomycetous fungus responsible for Pneumocystis pneumonia (PCP) in immunocompromised patients, affecting >500,000 patients per year (www.gaffi.org). The understanding of its epidemiology is limited by the lack of standardised culture. Recent genotyping data suggests a limited genetic diversity o...

Mutations in the Dihydropteroate synthase (DHPS) gene of Pneumocystis jirovecii associate with failure of sulfa prophylaxis. They can develop by selection in patients receiving sulfa drugs, or be acquired via person-to-person transmission. DHPS mutations raise concern about decreasing efficacy of sulfa drugs, the main available therapeutic tool for...

Pneumocystis jirovecii pneumonia (PcP) remains a major cause of respiratory illness among immunosuppressed patients. PcP is difficult to diagnose, in particular in non-HIV-infected patients due to the lack of specific clinical data associated. Since P. jirovecii could not be cultivated for many years, microscopic visualization of cysts or trophic f...

Diagnosis of Pneumocystis pneumonia (PcP) relies on the detection of P. jirovecii in respiratory specimens obtained by invasive techniques. Thus, the development of a serological test is urgently needed as it will allow the diagnosis of PcP using blood, an inexpensive and non-invasive specimen. This study aims to combine the production of a multi-e...

In this study we determined the presence of IgM/IgG antibodies to Toxoplasma gondii in sera of 155 and 300 pregnant women from Lisbon (Portugal) and Luanda (Angola), respectively, and evaluated the potential risk factors associated with this infection. DNA detection was performed by PCR assays targeting T. gondii regions (RE/B1). Overall, 21·9% (10...

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_Pneumocystis jirovecii_ is a human specific uncultivable ascomycetous fungus, for which the reservoir is immunocompetent human individuals. Immunocompromised patients are at risk of developing pneumocystis pneumonia (PCP) when exposed to _P.jirovecii_ through their immediate environment. A recently described short tandem repeat (STR) typing strate...

Pneumocystis jirovecii can cause life-threatening pneumonia following treatment for haematological malignancies or after HSCT. The mortality rate of P. jirovecii pneumonia (PCP) in these patients is 30%–60%, especially after HSCT. The clinical presentation of PCP in haematology differs from that associated with HIV infection, with the disease being...

The Fifth European Conference on Infections in Leukaemia (ECIL-5) convened a meeting to establish evidence-based recommendations for using tests to diagnose Pneumocystis jirovecii pneumonia (PCP) in adult patients with haematological malignancies. Immunofluorescence assays are recommended as the most sensitive microscopic method (recommendation A-I...

The 5th European Conference on Infections in Leukaemia (ECIL-5) meeting aimed to establish evidence-based recommendations for the prophylaxis of Pneumocystis jirovecii pneumonia (PCP) in non-HIV-infected patients with an underlying haematological condition, including allogeneic HSCT recipients. Recommendations were based on the grading system of th...

Pneumocystis jirovecii causes severe interstitial pneumonia (PcP) in immunosuppressed patients. This multicenter study assessed the distribution frequencies of epidemiologically relevant genetic markers of P. jirovecii in different geographic populations from Portugal, the USA, Spain, Cuba and Mozambique, and the relationship between the molecular...

To investigate the transmission of species of Cryptosporidium Tyzzer, 1907 in Timis County, Romania, 48 isolates of Cryptosporidium coccidia from 11 children, 29 calves and eight pigs were characterised by molecular analysis of two loci (SSU rRNA and 60-kDa glycoprotein gene). Overall, 22 isolates were amplified and sequence analyses revealed that...

The diagnosis of Pneumocystis pneumonia (PcP) relies on microscopic visualization of P. jirovecii organisms or DNA detection in pulmonary specimens. This study aimed to assess the usefulness of (1-3)-β-D-Glucan (BG), Krebs von den Lungen-6 antigen (KL-6), lactate dehydrogenase (LDH) and S-adenosyl Methionine (SAM) as serological biomarkers in the d...

Rare systemic studies concerning prevalence of intestinal parasites in children have been conducted in the second smallest country in Africa, the Democratic Republic of São Tomé and Príncipe. Fecal specimens from 348 children (214 in-hospital attending the Aires de Menezes Hospital and 134 from Agostinho Neto village) in São Tome Island were studie...

Pneumocystis e pneumocistose: 1 Encontro Ibero-americano e dos Países de Língua Oficial Portuguesa (Pneumocystis and Pneumocystosis: first meeting of experts from Latin-American and Portuguese-speaking countries) Lisbon, Portugal, 24–26 October 2013 The Pneumocystis and Pneumocystosis: first meeting of experts from Latin-American and Portuguese-spe...

Pneumocystis pneumonia (PcP) is a major HIV-related illness caused by Pneumocystis jirovecii. Definitive diagnosis of PcP requires microscopic detection of P. jirovecii in pulmonary specimens. The objective of this study was to evaluate the usefulness of two serum markers in the diagnosis of PcP. Serum levels of (1-3)-beta-d-glucan (BG) and lactate...

A pneumonia por Pneumocystis jirovecii (pneumocistose ou PPc) é um importante factor de morbilidade e mortalidade nos doentes com a síndroma de imunodeficiência adquirida (sida). A pneumocistose é, também, um problema emergente nos imunocomprometidos, seronegativos para vírus da imunodeficiência humana (VIH), devido ao número crescente de doentes i...

Pneumocystis pneumonia (PcP) is a major cause of mortality and morbidity in immunocompromised patients. There are limited alternative therapeutic choices to trimethoprim-sulfamethoxazole (TMP-SMX) which is the standard first line therapy/prophylaxis for PcP. The efficacy of low doses of caspofungin and caspofungin in association with TMP-SMX standa...

It is well established that HIV patients are at high risk of opportunistic infections (OI), like the ones caused by Pneumocystis jirovecii, a worldwide pathogen implicated in interstitial pneumonia (PcP). We present a case of a newly diagnosed HIV-1 patient with multiple OI, including a persistent form of PcP, an invasive aspergillosis (IA), cytome...

It is well established that HIV patients are at high risk of opportunistic infections (OI), like the ones caused by Pneumocystis jirovecii, a worldwide pathogen implicated in interstitial pneumonia (PcP). We present a case of a newly diagnosed HIV-1 patient with multiple OI, including a persistent form of PcP, an invasive aspergillosis (IA), cytome...

With the discovery that the coccidian parasite Crypto-sporidium sp. can cause severe symptoms in humans, many diagnostic techniques were quickly implemented such as microscopic visualization, immunofluorescence and PCR. Currently, there is no effective drug treatment and none of the current diagnostic methods is 100% accurate. In this study, a BALB...

The 13th International Workshops on Opportunistic Protists (IWOP-13) was held November 13 to 15, 2014 in Seville, Spain. The objectives of the IWOP meetings are to: (1) Serve as a forum for exchange of new information among active researchers concerning the basic biology, molecular genetics, immunology, biochemistry, pathogenesis, drug development,...

Cryptosporidium parvum is an intracellular parasite causing enteritis which can become life-threatening in immunocompromised host. Immunoregulatory T cells play a central role in the regulatory network of the host. Here, we proposed to characterize the populations of immune cells during infection and reinfection with C. parvum. Four-week-old BALB/C...

Toxoplasmosis is an important zoonosis worldwide. Here we determined the presence of Toxoplasma gondii antibodies in sera and T. gondii DNA in feces of 215 domestic cats from veterinary clinics in the Lisbon area; 44 (20.5%) had anti-T. gondii IgG antibodies by the modified agglutination test (cut-off 1:40) and DNA was detected in 16 (35.6%) of 45...

A review was conducted to examine published works that focus on the complex epidemiology of Enterocytozoon bieneusi infection in humans. Studies on the prevalence of these emerging microsporidian pathogens in humans, in developed and developing countries, the different clinical spectra of E. bieneusi intestinal infection in children, in different s...

Pneumocystis jirovecii (Pj) is an opportunistic pathogen responsible for one of the most severe infections in immunocompromised patients, Pneumocystis pneumonia (PcP). Currently, the laboratory diagnosis of PcP is based on cytochemical staining, indirect immunofluorescence with monoclonal antibodies and PCR on induced sputum and bronchoalveolar lav...

Clin Microbiol Infect 2012; 18: E177–E184 Specific single-nucleotide polymorphisms (SNPs) are recognized as important DNA sequence variations influencing the pathogenesis of Pneumocystis jirovecii and the clinical outcome of Pneumocystis pneumonia, which is a major worldwide cause of illness among immunocompromised patients. Genotyping platforms fo...

Despite recent advances in the understanding and diagnosis of emerging microsporidian pathogens, more research is necessary to elucidate their complex epidemiology. In fact, studies that reflect true human-infecting microsporidian prevalence are still inadequate. The present 10-year study was undertaken to examine the occurrence of Microsporidia in...

Thus far, genotyping of Enterocytozoon bieneusi has been based solely on DNA sequence analysis of the internal transcribed spacer (ITS) of the rRNA gene. Both host-adapted and zoonotic (human-pathogenic) genotypes of E. bieneusi have been identified. In this study, we searched for microsatellite and minisatellite sequences in the whole-genome seque...

Pneumocystis jirovecii pneumonia (PcP) is a major cause of respiratory illness in patients with AIDS. The identification of multiple single-nucleotide polymorphisms (SNPs) at three distinct P. jirovecii loci encoding dihydrofolate reductase (DHFR), mitochondrial large-subunit rRNA (mtLSU rRNA), and superoxide dismutase (SOD) was achieved using mult...