Toxoplasma gondii: Infection natural congenital in cattle and an experimental inoculation of gestating cows with oocysts

Two studies, of a natural infection and an experimental infection, were performed in order to study congenital transmission of Toxoplasma gondii in cattle. In the first study, 50 fetuses were harvested from gestating cows that were eutanasied at a municipal slaughterhouse in Jaboticabal, São Paulo state, Brazil. In the second study, 11 gestating cows were divided into four groups for inoculation with T. gondii: GI consisted of three cows inoculated with 1.0 x 10(5) oocysts during their first trimester of gestation; GII consisted of three cows inoculated with 1.0 x 10(5) oocysts during their second trimester of gestation; GIII consisted of three cows inoculated with 1.0 x 10(5) oocysts during their last trimester of gestation; and GIV consisted of two control cows, one during its first and the other during its second trimester of gestation. In both studies, the presence of T. gondii was confirmed both indirectly by immunofluorescence assay (IFAT). In the natural infection experiment, 18% (9/50) of the gestating cows were confirmed to have specific antibodies (IFAT - 1:64) against T. gondii. The bioassay was able to diagnose the presence of T. gondii in the tissue samples from three calves. In the second experiment, the nine cows from groups I, II and III presented with specific antibodies (IFAT) against T. gondii. In contrast, T. gondii could not be detected by IFAT, histopathological examination or the bioassay in any of the nine calves born to cows experimentally infected with T. gondii oocysts. Based on the results from both studies, we conclude that congenital infection of T. gondii in cattle, while infrequent, does occur naturally. The pathogenicity of the strain of T. gondii may influence the likelihood of this route of transmission. (C) 2010 Elsevier B.V. All rights reserved.

Toxoplasma gondii infection in wild boars (Sus scrofa) bred in Brazil

Domestic pigs are considered to be important sources of Toxoplasma gondii infection for humans. Due to the increased consumption of wild boar meat in Brazil, this species may also be an important source of the parasite. The objective of the present study was to detect T. gondii infection in 306 blood samples collected from wild boars bred in the state of São Paulo, Brazil. Samples were analyzed using the modified agglutination test (MAT), and 14 (4.5%) of them yielded positive results. Modern breeding techniques may have contributed to the low frequency of infection observed. Results indicated that wild boars were exposed to T. gondii and that the consumption of this kind of meat may represent a source of infection for humans. (C) 2009 Elsevier B.V. All rights reserved.

Chlamydophila psittaci and Toxoplasma gondii infection in pigeons (Columba livia) from São Paulo State, Brazil

Pigeons (Columba livia) cohabit with humans in urban and rural areas, representing a public health problem since microorganisms are transmitted through the inhalation of dust from their dry feces (chlamydiosis) and through ingestion of their undercooked or poorly refrigerated meat (toxoplasmosis). This study aimed to evaluate the presence of Chlamydophila psittaci and Toxoplasma gondii in pigeons from four cities in São Paulo State, Brazil. C psittaci was evaluated through hemi-nested polymerase chain reaction (hnPCR) using cloacal and tracheal swabs, whereas T. gondii specific antibodies were assessed by means of modified agglutination test (MAT), mouse brain and muscle bioassay, and polymerase chain reaction (PCR). To confirm the infection in mice, T. gondii antibodies were assayed by using indirect fluorescent antibody test (IFAT). Considering C. psittaci, 40/238 (16.8%; 95%CI 12.6-22.1%) samples were positive according to hnPCR, especially for the cities of São Paulo (42.5%) and Bauru (35%). As regards T. gondii, 12/238 (5%; 95%CI 2.9-8.6%) serum samples were positive according to MAT. of these, five samples had titer equal to 1:8; six samples, 1:16; and one sample, 1:32. Bioassay, IFAT and PCR were negative for mouse toxoplasmosis. The absence of T. gondii antibodies suggests that pigeons may be infected with a low concentration of the agent, not detected by the antigen test. Thus, C. psittaci represents an actual problem concerning bird health. (C) 2010 Elsevier B.V. All rights reserved.

Recrudescence of Toxoplasma gondii infection in chronically infected rats (Rattus norvegicus)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Epidemiological Aspects in the Leptospira spp. and Toxoplasma gondii Infection in Horses from Botucatu, São Paulo, Brazil

Leptospirosis and toxoplasmosis are zoonoses with high importance because of the economic and public health impact. This study was aimed to determine the seroprevafence of leptospirosis and toxoplamosis in 714 serum samples of horses from different farms from Botucatu, São Paulo, Brazil. The samples were researched for Toxoplasma gondii antibodies by indirect immunofluorescence antibody test (IFAT) and for Leptospira spp. antibodies by microscopic agglutination test. of 714 serum samples, 128 (17.9%; 95% Cl: 15.3%-20.9%) were positive for one or more serovars of Leptospira spp., with icterohaemorrhagiae, canicola, and castellonis as the most prevalent serovars, whereas 42 (5.9%; 95% CI: 4.4%-7.9%) were positive for T gondii, of which 33 samples (78.57%; 95% CI: 64.0%-88.2%) presented a titer of 16, 7 (16.7%; 95% CI: 8.4%-30.7%) a titer of 64, and 1 (2.38%; 95% CI: 0.6%-12.3%) a titer of 256. No significant difference was found among the results obtained and the associated variables such as age and sex. (C) 2012 Elsevier B.V. All rights reserved.

Seroprevalence of Toxoplasma gondii infection in cats from Curitiba, Paraná, Brazil

A toxoplasmose é uma zoonose de distribuição mundial, causada pelo protozoário Toxoplasma gondii que infecta os vertebrados de sangue quente. Este estudo objetiva estabelecer a prevalência de anticorpos anti-Toxoplasma gondii e o estudo de associação em uma população de gatos domésticos atendidos em uma clínica veterinária exclusiva de gatos localizada em Curitiba, estado do Paraná, Brasil. As amostras de soro foram obtidas e processadas pela reação de imunofluorescência indireta IgG. Títulos de anticorpos foram encontrados em 46/282 (16,3%) das amostras analisadas, com título de 16 em oito gatos, 64 em 23, 256 em 14 e 1024 em um gato. Diferenças estatísticas não foram encontradas no estudo de associação entre idade, gênero e região da cidade (p > 0,05). Nenhuma diferença significativa foi encontrada para qualquer variável, quando comparando a soropositividade com a ocorrência do possível fator de risco. A soroprevalência foi relativamente menor quando comparada a outras regiões brasileiras, provavelmente por serem gatos de proprietários, que tinham hábito domiciliado e alimentação restrita baseada em alimentos industrializados, com acesso restrito a rua e sem acesso a caça. em conclusão, a baixa soroprevalência de toxoplasmose felina pode estar relacionada a gatos com proprietários devido aos cuidados alimentares e acesso restrito à rua, e também pode estar associada à baixa exposição ambiental local

Prevalence and risk factors for Toxoplasma gondii infection in certified and non-certified pig breeding farms in the Toledo microregion, PR, Brazil

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.

Sensitivity and specificity of serological tests, histopathology and immunohistochemistry for detection of Toxoplasma gondii infection in domestic chickens

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A SURVEY OF NEOSPORA CANINUM AND TOXOPLASMA GONDII INFECTION IN URBAN RODENTS FROM BRAZIL

Toxoplasma gondii is a protozoan parasite that infects humans and other warm-blooded animals; it uses feral and domestic cats as the definitive hosts. Neospora caninum is a protozoan parasite of animals whose life cycle is very similar to T. gondii but uses canids as definitive hosts. Small rodents play an important role in the life cycle of T. gondii, and a few findings indicated that they may be natural intermediate hosts for N. caninum. The present study was aimed at identifying infections by T. gondii and N. caninum in urban rodents. Infections by T. gondii were quantified using isolation of the parasite by bioassay in mice; molecular methods were also used for both parasites. Overall, 217 rodents were captured. Brain and heart tissues of all rodents were bioassayed in mice for the detection of T. gondii infection. Brain and heart tissues of 121 rodents had the DNA extracted for molecular analysis. Toxoplasma gondii was isolated by bioassay from a single rodent. From the 121 rodents tested for the presence of T. gondii DNA, 2 animals were positive. In contrast, DNA of N. caninum was not detected in any of the samples. In conclusion, the surveys of N. caninum and T. gondii infection in Rattus rattus, Rattus norvegicus, and Mus musculus captured in urban areas of Sao Paulo reveal a striking low frequency of occurrence of these infections.

Heme oxygenase-1 activity is involved in the control of Toxoplasma gondii infection in the lung of BALB/c and C57BL/6 and in the small intestine of C57BL/6 mice

Heme oxygenase-1 (HO-1) is an enzyme that catabolizes free heme, which induces an intense inflammatory response. The expression of HO-1 is induced by different stimuli, triggering an anti-inflammatory response during biological stress. It was previously verified that HO-1 is able to induce indoleamine 2,3-dioxygenase (IDO), an enzyme that is induced by IFN-γ in Toxoplasma gondii infection. To verify the role of HO-1 during in vivo T. gondii infection, BALB/c and C57BL/6 mice were infected with the ME49 strain and treated with zinc protoporphyrin IX (ZnPPIX) or hemin, which inhibit or induce HO-1 activity, respectively. The results show that T. gondii infection induced high levels of HO-1 expression in the lung of BALB/c and C57BL6 mice. The animals treated with ZnPPIX presented higher parasitism in the lungs of both lineages of mice, whereas hemin treatment decreased the parasite replication in this organ and in the small intestine of infected C57BL/6 mice. Furthermore, C57BL/6 mice infected with T. gondii and treated with hemin showed higher levels of IDO expression in the lungs and small intestine than uninfected mice. In conclusion, our data suggest that HO-1 activity is involved in the control of T. gondii in the lungs of both mouse lineages, whereas the hemin, a HO-1 inducer, seems to be involved in the control of parasitism in the small intestine of C57BL/6 mice.

Seropositivity and Risk Factors Associated with Toxoplasma gondii Infection in Wild Birds from Spain

Toxoplasma gondii is a zoonotic intracellular protozoan parasite of worldwide distribution that infects many species of warm-blooded animals, including birds. To date, there is scant information about the seropositivity of T. gondii and the risk factors associated with T. gondii infection in wild bird populations. In the present study, T. gondii infection was evaluated on sera obtained from 1079 wild birds belonging to 56 species (including Falconiformes (n = 610), Strigiformes (n = 260), Ciconiiformes (n = 156), Gruiformes (n = 21), and other orders (n = 32), from different areas of Spain. Antibodies to T. gondii (modified agglutination test, MAT titer ≥1:25) were found in 282 (26.1%, IC95%:23.5–28.7) of the 1079 birds. This study constitute the first extensive survey in wild birds species in Spain and reports for the first time T. gondii antibodies in the griffon vulture (Gyps fulvus), short-toed snake-eagle (Circaetus gallicus), Bonelli's eagle (Aquila fasciata), golden eagle (Aquila chrysaetos), bearded vulture (Gypaetus barbatus), osprey (Pandion haliaetus), Montagu's harrier (Circus pygargus), Western marsh-harrier (Circus aeruginosus), peregrine falcon (Falco peregrinus), long-eared owl (Asio otus), common scops owl (Otus scops), Eurasian spoonbill (Platalea leucorodia), white stork (Ciconia ciconia), grey heron (Ardea cinerea), common moorhen (Gallinula chloropus); in the International Union for Conservation of Nature (IUCN) “vulnerable” Spanish imperial eagle (Aquila adalberti), lesser kestrel (Falco naumanni) and great bustard (Otis tarda); and in the IUCN “near threatened” red kite (Milvus milvus). The highest seropositivity by species was observed in the Eurasian eagle owl (Bubo bubo) (68.1%, 98 of 144). The main risk factors associated with T. gondii seropositivity in wild birds were age and diet, with the highest exposure in older animals and in carnivorous wild birds. The results showed that T. gondii infection is widespread and can be at a high level in many wild birds in Spain, most likely related to their feeding behaviour.

Serological survey of Toxoplasma gondii infection in free-ranging Eurasian lynx (Lynx lynx) from Sweden

To investigate the prevalence of Toxoplasma gondii infection in free-ranging Eurasian lynx (Lynx lynx) in Sweden, serosanguinous fluids and feces were collected from 207 carcasses of lynx killed or found dead from 1996 to 1998. Sera were tested for antibodies against T. gondii by the direct agglutination test, and 156 (75.4%) of the sera tested positive at antibody titers>or=40. Antibody prevalence was significantly lower in lynx originating from the northern parts of Sweden than in lynx from the more southern regions that are more densely populated by humans. Age-related differences also were found, with a significantly lower prevalence (55%) in juvenile (<1-yr-old) than in subadult and adult animals (82%). There was no significant difference in seroprevalence between males and females. Oocysts typical of T. gondii were not detected in any of the fecal samples.

Toxoplasma gondii Infection in Kyrgyzstan: Seroprevalence, Risk Factor Analysis, and Estimate of Congenital and AIDS-Related Toxoplasmosis

Background HIV-prevalence, as well as incidence of zoonotic parasitic diseases like cystic echinococcosis, has increased in the Kyrgyz Republic due to fundamental socio-economic changes after the breakdown of the Soviet Union. The possible impact on morbidity and mortality caused by Toxoplasma gondii infection in congenital toxoplasmosis or as an opportunistic infection in the emerging AIDS pandemic has not been reported from Kyrgyzstan. Methodology/Principal Findings We screened 1,061 rural and 899 urban people to determine the seroprevalence of T. gondii infection in 2 representative but epidemiologically distinct populations in Kyrgyzstan. The rural population was from a typical agricultural district where sheep husbandry is a major occupation. The urban population was selected in collaboration with several diagnostic laboratories in Bishkek, the largest city in Kyrgyzstan. We designed a questionnaire that was used on all rural subjects so a risk-factor analysis could be undertaken. The samples from the urban population were anonymous and only data with regard to age and gender was available. Estimates of putative cases of congenital and AIDS-related toxoplasmosis in the whole country were made from the results of the serology. Specific antibodies (IgG) against Triton X-100 extracted antigens of T. gondii tachyzoites from in vitro cultures were determined by ELISA. Overall seroprevalence of infection with T. gondii in people living in rural vs. urban areas was 6.2% (95%CI: 4.8–7.8) (adjusted seroprevalence based on census figures 5.1%, 95% CI 3.9–6.5), and 19.0% (95%CI: 16.5–21.7) (adjusted 16.4%, 95% CI 14.1–19.3), respectively, without significant gender-specific differences. The seroprevalence increased with age. Independently low social status increased the risk of Toxoplasma seropositivity while increasing numbers of sheep owned decreased the risk of seropositivity. Water supply, consumption of unpasteurized milk products or undercooked meat, as well as cat ownership, had no significant influence on the risk for seropositivity. Conclusions We present a first seroprevalence analysis for human T. gondii infection in the Kyrgyz Republic. Based on these data we estimate that 173 (95% CI 136–216) Kyrgyz children will be born annually to mothers who seroconverted to toxoplasmosis during pregnancy. In addition, between 350 and 1,000 HIV-infected persons are currently estimated to be seropositive for toxoplasmosis. Taken together, this suggests a substantial impact of congenital and AIDS-related symptomatic toxoplasmosis on morbidity and mortality in Kyrgyzstan.

A dichotomous role for nitric oxide during acute Toxoplasma gondii infection in mice

Production of nitric oxide by macrophages is believed to be an important microbicidal mechanism for a variety of intracellular pathogens, including Toxoplasma gondii. Mice with a targeted disruption of the inducible nitric oxide synthase gene (iNOS) were infected orally with T. gondii tissue cysts. Time to death was prolonged compared with parental controls. Histologic analysis of tissue from infected mice showed scattered small foci of inflammation with parasites in various tissues of iNOS−/− mice, whereas tissue from the parental C57BL/6 mice had more extensive tissue inflammation with few visible parasites. In particular, extensive ulceration and necrosis of distal small intestine and fatty degeneration of the liver was seen in the parental mice at day 7 postinfection, as compared with the iNOS−/− mice where these tissues appeared normal. Serum interferon γ and tumor necrosis factor α levels postinfection were equally elevated in both mouse strains. Treatment of the parental mice with a NO synthase inhibitor, aminoguanidine, prevented early death in these mice as well as the hepatic degeneration and small bowel necrosis seen in acutely infected control parentals. These findings indicate that NO production during acute infection with T. gondii can kill intracellular parasites but can be detrimental, even lethal, to the host.