991 resultados para parasite prevalence


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A infecção pelo Toxoplasma gondii tem sido diagnosticada em suínos em todo o mundo. Perdas econômicas geralmente estão relacionadas a distúrbios reprodutivos. A infecção pelo Toxoplasma tem também importância em saúde pública, já que cistos teciduais do parasito podem persistir na carne e subprodutos oriundos de suínos, que servirão de fontes de infecção para o ser humano. O objetivo deste trabalho foi verificar a frequência e os fatores de risco associados à infecção pelo Toxoplasma em granjas de reprodutores suídeos certificados ou não da microrregião de Toledo, no Paraná, que inclui os municípios de Toledo, Nova Santa Rosa, São José das Palmeiras e São Pedro do Iguaçú. A frequência relativa de infecção foi 13,4%, sem diferença com o tipo de granja. A análise de regressão logística demonstrou os seguintes fatores associados à infecção: não utilização de funcionários separados por área da granja, o acesso de animais ao cocho de ração e ao reservatório de água, a não utilização de tampa neste reservatório, a não prevenção de roedores, o número e peso médio de leitões ao desmame por porca.

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The determination of mean intensity of parasitism for colony-forming sessile protozoan such as Epistylis has been a great problem in parasitological studies. Some alternatives have been proposed by researchers for laboratory and field conditions. This study describes the criteria to establish the parasitic intensity score for epistylidid infestation in fish. Parasite distribution and the host-parasite relationship in four species of Brazilian cultured catfish and their hybrids are discussed. The highest prevalence rates were found in the hybrid jundiara, Leiarius marmoratus male × Pseudoplatystoma reticulatum female (96.4 %), followed by jurupoca, Hemisorubim platyrhynchos (60 %), and the hybrid surubim, Pseudoplatystoma corruscans male × P. reticulatum female (52.7 %). Positive correlation between parasitic intensity score and the fish size, weight, and relative condition factor were also observed. These findings indicate that Epistylis infestation in Brazilian catfish is an emerging disease in cultured fish. © 2012 Springer-Verlag.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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This was a cross-sectional study which analyzed the prevalence and the clinical and immunological spectrum of canine Leishmania (L.) infantum chagasi infection in a cohort of 320 mongrel dogs living in an endemic area of American visceral leishmaniasis in the Amazonian Brazil by using, mainly, the indirect fluorescence antibody test (IFAT-IgG) and the delayed-type hypersensitivity (DTH), and the parasite research by the popliteal lymph node aspiration. The IFAT and DTH reactivity recognized three different immune response profiles: (1) IFAT((+))/DTH(-) (107 dogs), (2) IFAT((-))/DTH(+) (18 dogs), and (3) IFAT((+))/DTH(+) (13 dogs), providing an overall prevalence of infection of 43 % (138/320). Thus, the specific prevalence of IFAT ((+)) /DTH ((-)) 33.4 % (107/320) was higher than those of IFAT ((-)) /DTH ((+)) 5.6 % (18/320) and IFAT ((+)) /DTH ((+)) 4.0 % (13/320). Moreover, the frequency of these profiles among 138 infected dogs showed that the IFAT ((+)) /DTH ((-)) rate of 77.5 % (107/138) was also higher than those of 13.0 % (18/138) of IFAT ((-)) /DTH ((+)) and 9.5 % (13/138) of IFAT ((+)) /DTH ((+)) rates. The frequency of asymptomatic dogs (76 %-105) was higher than those of symptomatic (16.6 %-23) and oligosymptomatic ones (7.4 %-10). A total of 16 (11.6 %) L. (L.) i. chagasi isolates were obtained from infected dogs, all from the IFAT ((+)) /DTH ((-)) profile: 41 % (9/22) from symptomatic, 33.3 % (3/9) from oligosymptomatic, and 5.2 % (4/76) from asymptomatic dogs. These findings strongly suggested that despite the higher frequency of asymptomatic dogs (76 %-105), the majority (72.4 %-76) was characterized by the IFAT ((+)) /DTH ((-)) profile with a doubtful immunogenetic resistance against infection.

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Schistosomiasis constitutes a major public health problem, with an estimated 200 million individuals infected worldwide and 700 million people living in risk areas. In Brazil there are areas of high, medium and low endemicity. Studies have shown that in endemic areas with a low prevalence of Schistosoma infection the sensitivity of parasitological methods is clearly reduced. Consequently diagnosis is often impeded due to the presence of false-negative results. The aim of this study is to present the PCR reamplification (Re-PCR) protocol for the detection of Schistosoma mansoni in samples with low parasite load (with less than 100 eggs per gram (epg) of feces). Three methods were used for the lysis of the envelopes of the S. mansoni eggs and two techniques of DNA extraction were carried out. Extracted DNA was quantified, and the results suggested that the extraction technique, which mixed glass beads with a guanidine isothiocyanate/phenol/chloroform (GT) solution, produced good results. PCR reamplification was conducted and detection sensitivity was found to be five eggs per 500 mg of artificially marked feces. The results achieved using these methods suggest that they are potentially viable for the detection of Schistosoma infection with low parasite load.

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The protozoan parasite Toxoplasma gondii infects almost all warm blooded animal species including humans, and is one of the most prevalent zoonotic parasites worldwide. Post-natal infection in humans is acquired through oral uptake of sporulated T. gondii oocysts or by ingestion of parasite tissue cysts upon consumption of raw or undercooked meat. This study was undertaken to determine the prevalence of oocyst-shedding by cats and to assess the level of infection with T. gondii in meat-producing animals in Switzerland via detection of genomic DNA (gDNA) in muscle samples. In total, 252 cats (44 stray cats, 171 pet cats, 37 cats with gastrointestinal disorders) were analysed coproscopically, and subsequently species-specific identification of T. gondii oocysts was achieved by Polymerase Chain Reaction (PCR). Furthermore, diaphragm samples of 270 domestic pigs (120 adults, 50 finishing, and 100 free-range animals), 150 wild boar, 250 sheep (150 adults and 100 lambs) and 406 cattle (47 calves, 129 heifers, 100 bulls, and 130 adult cows) were investigated by T. gondii-specific real-time PCR. For the first time in Switzerland, PCR-positive samples were subsequently genotyped using nine PCR-restriction fragment length polymorphism (PCR-RFLP) loci (SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and Apico) for analysis. Only one of the cats shed T. gondii oocysts, corresponding to a T. gondii prevalence of 0.4% (95% CI: 0.0-2.2%). In meat-producing animals, gDNA prevalence was lowest in wild boar (0.7%; 95% CI: 0.0-3.7%), followed by sheep (2.0%; 95% CI: 0.1-4.6%) and pigs (2.2%; 95% CI: 0.8-4.8%). The highest prevalence was found in cattle (4.7%; 95% CI: 2.8-7.2%), mainly due to the high prevalence of 29.8% in young calves. With regard to housing conditions, conventional fattening pigs and free-range pigs surprisingly exhibited the same prevalence (2.0%; 95% CI: 0.2-7.0%). Genotyping of oocysts shed by the cat showed T. gondii with clonal Type II alleles and the Apico I allele. T. gondii with clonal Type II alleles were also predominantly observed in sheep, while T. gondii with mixed or atypical allele combinations were very rare in sheep. In pigs and cattle however, genotyping of T. gondii was often incomplete. These findings suggested that cattle in Switzerland might be infected with Toxoplasma of the clonal Types I or III, atypical T. gondii or more than one clonal Type.

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Haemotrophic mycoplasmas (also known as haemoplasmas), small bacterias which parasite the surface of erythrocytes, have been described in several species. Recently, molecular methods were developed for the diagnosis of haemoplasma infection. The presented study describes the first detection and the investigation of prevalence of "Candidatus Mycoplasma haemolamae" in South American Camelids in Switzerland. A random sample of the latter population was tested for haemoplasma infections using real-time PCR. The infection was detected in 18.6% of the animals and was found both in indigenous and in imported camelids. Of the tested herds 39,1% harboured at least one animal positive for haemoplasmas in PCR. There was no difference in prevalence between male and female animals and llamas and alpacas, respectively. Furthermore, the prevalence of infection was not significantly different in diseased animals compared to healthy camelids. From the latter observation and the fact that the high prevalence was accompanied by an undetectable incidence, we concluded that the pathogenicity of "Candidatus Mycoplasma haemolamae" may be low.

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Trichinella spp. larvae have not been detected in Swiss pigs, horses, or wild boar for many decades, whereas the parasite was repeatedly isolated from red foxes and Eurasian lynxes. Whenever the isolated larvae could be subjected to genotyping, T. britovi was found as infective agent. The present study was initiated to re-assess the epidemiological situation of Trichinella infection in Swiss carnivorous wildlife, namely in red foxes and lynxes. Tissue samples from 1,298 foxes were collected between 2006 and 2007, and those of 55 lynxes between 1999 and 2007. All samples were tested by a standard artificial digestion method and a multiplex-PCR to determine the species and/or genotypes of recovered larvae. Trichinella larvae were found in 21 foxes (1.6%) and 15 lynxes (27.3%), and T. britovi was identified as infecting species in all cases. The geographic distribution of positive foxes showed two main clusters: one in Central Switzerland and one in the West of the country, where also many lynxes were found to be positive. While the prevalence for Trichinella infection in foxes was not statistically correlated with sex or age class, the prevalence in lynx was significantly higher in males compared to females, and in adults compared to juveniles.

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Switzerland is officially free from bovine Tritrichomonas foetus. While bulls used for artificial insemination (AI) are routinely examined for this pathogen, bulls engaged in natural mating, as well as aborted fetuses, are only very sporadically investigated, indicating that the disease awareness for bovine tritrichomoniasis is low. Natural mating in cattle is becoming increasingly popular in Switzerland. Accordingly, a re-introduction/re-occurrence of T. foetus in cattle seems possible either via resurgence from a yet unknown bovine reservoir, or via importation of infected cattle. The low disease awareness for bovine tritrichomoniasis might favor an unnoticed re-establishment of T. foetus in the Swiss cattle population. The aim of our study was thus to search for the parasite, and if found, to assess the prevalence of bovine T. foetus in Switzerland. We included (1) bulls over two years of age used in natural mating and sent to slaughter, (2) bulls used for natural service in herds with or without fertility problems and (3) aborted fetuses. Furthermore, the routinely examined bulls used for AI (4) were included in this study. In total, 1362 preputial samples from bulls and 60 abomasal fluid samples of aborted fetuses were analyzed for the presence of T. foetus by both in vitro cultivation and molecular analyses. The parasite could not be detected in any of the samples, indicating that the maximal prevalence possibly missed was about 0.3% (95% confidence). Interestingly, in preputial samples of three bulls of category 1, apathogenic Tetratrichomonas sp. was identified, documenting a proof-of-principle for the methodology used in this study.

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Toxoplasma gondii is a coccidian parasite with a global distribution. The definitive host is the cat (and other felids). All warm-blooded animals can act as intermediate hosts, including humans. Sexual reproduction (gametogony) takes place in the final host and oocysts are released in the environment, where they then sporulate to become infective. In intermediate hosts the cycle is extra-intestinal and results in the formation of tachyzoites and bradyzoites. Tachyzoites represent the invasive and proliferative stage and on entering a cell it multiplies asexually by endodyogeny. Bradyzoites within tissue cysts are the latent form. T. gondii is a food-borne parasite causing toxoplasmosis, which can occur in both animals and humans. Infection in humans is asymptomatic in more than 80% of cases in Europe and North-America. In the remaining cases patients present fever, cervical lymphadenopathy and other non-specific clinical signs. Nevertheless, toxoplasmosis is life threatening if it occurs in immunocompromised subjects. The main organs involved are brain (toxoplasmic encephalitis), heart (myocarditis), lungs (pulmonary toxoplasmosis), eyes, pancreas and parasite can be isolated from these tissues. Another aspect is congenital toxoplasmosis that may occur in pregnant women and the severity of the consequences depends on the stage of pregnancy when maternal infection occurs. Acute toxoplasmosis in developing foetuses may result in blindness, deformation, mental retardation or even death. The European Food Safety Authority (EFSA), in recent reports on zoonoses, highlighted that an increasing numbers of animals resulted infected with T. gondii in EU (reported by the European Member States for pigs, sheep, goats, hunted wild boar and hunted deer, in 2011 and 2012). In addition, high prevalence values have been detected in cats, cattle and dogs, as well as several other animal species, indicating the wide distribution of the parasite among different animal and wildlife species. The main route of transmission is consumption of food and water contaminated with sporulated oocysts. However, infection through the ingestion of meat contaminated with tissue cysts is frequent. Finally, although less frequent, other food products contaminated with tachyzoites such as milk, may also pose a risk. The importance of this parasite as a risk for human health was recently highlighted by EFSA’s opinion on modernization of meat inspection, where Toxoplasma gondii was identified as a relevant hazard to be addressed in revised meat inspection systems for pigs, sheep, goats, farmed wild boar and farmed deer (Call for proposals -GP/EFSA/BIOHAZ/2013/01). The risk of infection is more highly associated to animals reared outside, also in free-range or organic farms, where biohazard measure are less strict than in large scale, industrial farms. Here, animals are kept under strict biosecurity measures, including barriers, which inhibit access by cats, thus making soil contamination by oocysts nearly impossible. A growing demand by the consumer for organic products, coming from free-range livestock, in respect of animal-welfare, and the desire for the best quality of derived products, have all led to an increase in the farming of free-range animals. The risk of Toxoplasma gondii infection increases when animals have access to environment and the absence of data in Italy, together with need for in depth study of both the prevalence and genotypes of Toxoplasma gondii present in our country were the main reasons for the development of this thesis project. A total of 152 animals have been analyzed, including 21 free-range pigs (Suino Nero race), 24 transhumant Cornigliese sheep, 77 free-range chickens and 21 wild animals. Serology (on meat juice) and identification of T. gondii DNA through PCR was performed on all samples, except for wild animals (no serology). An in-vitro test was also applied with the aim to find an alternative and valid method to bioassay, actually the gold standard. Meat samples were digested and seeded onto Vero cells, checked every day and a RT-PCR protocol was used to determine an eventual increase in the amount of DNA, demonstrating the viability of the parasite. Several samples were alos genetically characterized using a PCR-RFLP protocol to define the major genotypes diffused in the geographical area studied. Within the context of a project promoted by Istituto Zooprofilattico of Pavia and Brescia (Italy), experimentally infected pigs were also analyzed. One of the aims was to verify if the production process of cured “Prosciutto di Parma” is able to kill the parasite. Our contribution included the digestion and seeding of homogenates on Vero cells and applying the Elisa test on meat juice. This thesis project has highlighted widespread diffusion of T. gondii in the geographical area taken into account. Pigs, sheep, chickens and wild animals showed high prevalence of infection. The data obtained with serology were 95.2%, 70.8%, 36.4%, respectively, indicating the spread of the parasite among numerous animal species. For wild animals, the average value of parasite infection determined through PCR was 44.8%. Meat juice serology appears to be a very useful, rapid and sensitive method for screening carcasses at slaughterhouse and for marketing “Toxo-free” meat. The results obtained on fresh pork meat (derived from experimentally infected pigs) before (on serum) and after (on meat juice) slaughter showed a good concordance. The free-range farming put in evidence a marked risk for meat-producing animals and as a consequence also for the consumer. Genotyping revealed the diffusion of Type-II and in a lower percentage of Type-III. In pigs is predominant the Type-II profile, while in wildlife is more diffused a Type-III and mixed profiles (mainly Type-II/III). The mixed genotypes (Type-II/III) could be explained by the presence of mixed infections. Free-range farming and the contact with wildlife could facilitate the spread of the parasite and the generation of new and atypical strains, with unknown consequences on human health. The curing process employed in this study appears to produce hams that do not pose a serious concern to human health and therefore could be marketed and consumed without significant health risk. Little is known about the diffusion and genotypes of T. gondii in wild animals; further studies on the way in which new and mixed genotypes may be introduced into the domestic cycle should be very interesting, also with the use of NGS techniques, more rapid and sensitive than PCR-RFLP. Furthermore wildlife can become a valuable indicator of environmental contamination with T. gondii oocysts. Other future perspectives regarding pigs include the expansion of the number of free-range animals and farms and for Cornigliese sheep the evaluation of other food products as raw milk and cheeses. It should be interesting to proceed with the validation of an ELISA test for infection in chickens, using both serum and meat juice on a larger number of animals and the same should be done also for wildlife (at the moment no ELISA tests are available and MAT is the reference method for them). Results related to Parma ham do not suggest a concerning risk for consumers. However, further studies are needed to complete the risk assessment and the analysis of other products cured using technological processes other than those investigated in the present study. For example, it could be interesting to analyze products such as salami, produced with pig meat all over the Italian country, with very different recipes, also in domestic and rural contexts, characterized by a very short period of curing (1 to 6 months). Toxoplasma gondii is one of the most diffuse food-borne parasites globally. Public health safety, improved animal production and protection of endangered livestock species are all important goals of research into reliable diagnostic tools for this infection. Future studies into the epidemiology, parasite survival and genotypes of T. gondii in meat producing animals should continue to be a research priority.

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Schistosomiasis is the major neglected tropical helminthic disease worldwide. Current knowledge on the epidemiology of schistosomiasis in Guinea-Bissau is scarce and regarding to the absence of Schistosoma haematobium (S.h.). Therefore, a pilot study was undertaken to assess the prevalence and morbidity due to S.h. infection in randomly selected 90 children and adolescents aged 6 to 15 years. Prevalence of S.h. infection was 20.00 % (18/90). Microhematuria was observed in 61.11 % (11/18) of S.h.-egg-excreting vs. 37.50 % (27/72) of non-S.h.-egg-excreting children p ≤ 0.01. Body mass index (BMI) was less than 15 kg/m(2) in 52/90 (57.78 %) of all children and adolescents, but this proportion increased to 66.67 % (12/18) in S.h.-infected children who were more frequently stunted and wasted than in non-infected children. The mean weight-for-age Z score (WAZ) was reduced in S.h. infected as compared to non-infected children (-1.48 ± 1.08 SD vs. -0.80 ± 1.11 SD; p ≤ 0.01). To our knowledge, this is the first epidemiologic report on S. haematobium infection in Guinea-Bissau since 22 years. Even in this relatively small study sample, it appears that S. haematobium, besides the well-known symptoms such as hematuria, leads to significant, albeit commonly unacknowledged morbidity such as stunting and wasting. These observations underscore the notion that this vulnerable but neglected population urgently needs to be targeted for implementation of measures for treatment and control.

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A study of the prevalence, intensity and risk factors for soil-transmitted helminth infection was undertaken among school children aged 5-9 years attending a primary school in the fishing village in Peda Jalaripet, Visakhapatnam, South India. One hundred and eighty nine (92.6%) of 204 children were infected with one or more soil transmitted helminth parasites. The predominant parasite was Ascaris lumbricoides (prevalence of 91%), followed by Trichuris trichiura (72%) and hookworm (54%). Study of age-specific prevalence and intensity of infection revealed that the prevalence and intensity of A. lumbricoides infection was higher among younger children than older children. While aggregation of parasite infection was observed, hookworm infection was more highly aggregated than either A. lumbricoides or T. trichiura. Multivariate analysis identified parental occupation, child's age and mother's education as the potential risk factors contributing to the high intensity of A. lumbricoides infection. Children from fishing families with low levels of education of the mother had the highest intensity of A. lumbricoides infection. As the outcome of chemotherapy programs to control soil transmitted helminth infection is dependant on the dynamics of their transmission, there is a need for further studies to better define the role of specific factors that determine their prevalence, intensity and aggregation in different epidemiological settings. (C) 2004 Elsevier B.V. All rights reserved.

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Parasite infracommunities of the wrasse Coris batuensis (Bleeker, 1857) were analysed, and the relationship between endoparasites, diet, and host body weight inferred. Thirty-two fish were collected from Lizard Island, Australia. Percentage frequency of occurrence of prey categories in the gut was determined and abundance, prevalence and species richness of parasites were calculated. Fish mainly ate snails, bivalves and crustaceans and this did not vary with body weight. Thirty-one fish were parasitised with at least one of 21 taxa of parasites (4 ectoparasite and 17 endoparasite species), with an average of 4 species and 47 individuals per host. Tetraphyllidean cestode larvae were the most common and abundant group. Parasite life cycles are not known in detail, but small crustaceans, such as copepods and amphipods, are likely to be intermediate hosts for the cestodes, nematodes and digeneans found in C. batuensis. Molluscs, although frequent in the diet, may not be transmitting any parasite species. Numbers of prey and parasite species richness were not correlated. Composition, abundance and species richness of the parasite fauna were similar in hosts with different body weight, corresponding with C. batuensis having a similar diet throughout life. © Queensland Museum.

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Haemosporidians are vector-transmitted intracellular parasites that occur in many bird species worldwide and may have important implications for wild bird populations. Surveys of haemosporidians have traditionally focused on Europe and North America, and only recently have they been carried out in the Neotropics, where the prevalence and impacts of the disease have been less studied and are not well understood. In this study we carried out a survey in the endemic bird area of the Sierra Nevada de Santa Marta (SNSM), an isolated coastal massif in northern Colombia that contains a large number of biomes and that is experiencing high rates of habitat loss. We sampled birds from 25 species at 2 different altitudes (1640 and 2100 m asl) and determined avian haemosporidian infection by polymerase chain reaction and sequencing a portion of the cytochrome b (cyt b) gene of the parasite. From the sampled birds, 32.1% were infected by at least 1 of 12 unique cyt b lineages of haemosporidian genera: Plasmodium, Leucocytozoon, Haemoproteus, and subgenus Parahaemoproteus. We found a higher prevalence of avian haemosporidians at low altitudes (1640 m asl). All endemic bird species we sampled had at least one individual infected with avian haemosporidians. We also found evidence of higher overall prevalence among endemic rather than nonendemic birds, suggesting higher susceptibility in endemic birds. Overall, our findings suggest a high haemosporidian species richness in the bird community of the SNSM. Considering the rate of habitat loss that this area is experiencing, it is important to understand how avian haemosporidians affect bird populations; furthermore, more exhaustive sampling is required to fully comprehend the extent of avian haemosporidian infection in the area.

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Background: Although the Democratic Republic of Sao Tome and Principe (DRSTP) has undertaken school children-based deworming programs against intestinal parasitic infections (IPIs) using a single dose of mebendazole annually since 2005, it remains unclear as to the outcome to date. The present study intends to investigate the recent IPIs status among school children living in capital areas of the DRSTP. Methods: A total of 252 school children (121 boys and 131 girls) of grades 4 and 5 from 4 primary schools located in the capital areas participated in the present study and their fresh fecal specimens were examined for the presence of any parasites using the merthiolate- iodine-formaldehyde concentration method as conducted. Results: The overall prevalence of IPIs was 64.7% (163/ 252). No significant gender difference in prevalence between boys (67.8%) and girls (61.8%) was found (p = 0.3). The majority of school children were infected with a single species of parasite (55.8%). Altogether, 12 different intestinal parasite species were identified in DRSTP school children, of which 9 species were pathogenic and the remaining 3 were non-pathogenic. Conclusion: Improving the detection method, sanitation facilities and personal hygiene as well as utilizing combined drugs are all important measures to greatly reduce IPIs in DRSTP school children.