Seroprevalence of Toxoplasma gondii and Toxocara canis in a human rural population of Southern Rio Grande do Sul

Due to the growing population of pets, especially homeless dogs and cats, zoonoses still represent a significant public health problem. Toxoplasma gondii and Toxocara spp. are epidemiologically important zoonotic agents as they are etiological factors of human toxoplasmosis and toxocariasis, respectively. These parasites remain neglected even though they are substantially prevalent in rural areas. The aim of this study was to investigate T. gondii and T. canis seroprevalence and risk factors of seropositivity in a rural population in Pelotas municipality, Brazil. The study participants (n=344) were patients of a Basic Healthcare Unit (BHU) located in Cerrito Alegre. Blood samples were collected and tested for T. gondii antibodies by indirect immunofluorescence and T. canis antibodies by an indirect ELISA that targets an excreted-secreted antigen (TES). T. gondii seropositivity was 53.2%, with higher titers (1:256 - 1:1,024) in individuals who habitually eat pork, beef, or chicken, while T. canis seropositivity was 71.8% and concomitant T. gondii and T. canis seropositivity was 38.3%. Among the seropositivity risk factors assessed, only habitual undercooked meat consumption was significant (p = 0.046; OR = 3.7) for T. gondii and none of them were associated with T. canis seropositivity. Both parasites have a high prevalence in rural areas, which reinforces the need to invest in rural community education and health

Efeito protetor do probiótico Saccharomyces boulardii na infecção por Toxocara canis não se deve à ação direta sobre as larvas

SUMMARY In a previous study our group found that the probiotic Saccharomyces boulardii was capable of reducing the intensity of infection in mice with toxocariasis. In order to assess whether the mechanism involved would be a direct action of the probiotic on Toxocara canis larvae, this study was designed. Both probiotics were singly cultivated in plates containing RPMI 1640 medium and T. canis larvae. S. boulardii and B. cereus var. toyoi cultures presented 97.6% and 95.7% of larvae with positive motility, respectively, and absence of color by the dye trypan blue, not representing significant difference to the control group (p >; 0.05). We conclude that none of the probiotics showed in vitro effects on T. canis larvae and that the interaction with the intestinal mucosa is necessary for the development of the protective effect of S. boulardii.RESUMO Em estudo prévio nosso grupo verificou que o probiótico Saccharomyces boulardii foi capaz de reduzir a intensidade de infecção em camundongos com toxocaríase. Este estudo foi elaborado com o objetivo de avaliar se o mecanismo envolvido seria uma ação direta do probiótico sobre as larvas de Toxocara canis. Ambos probióticos foram cultivados, separadamente, em placas com meio RPMI1640 e larvas de T. canis. As culturas com S. boulardii e B. cereus var. toyoi apresentaram, respectivamente, 97,6% e 95,7% das larvas com motilidade positiva e ausência de coloração pelo azul de tripan, não representando diferença significativa do controle (p >; 0,05). Concluímos que nenhum dos probióticos apresentou efeito in vitro sobre as larvas de T. canis e que a interação com a mucosa intestinal é necessária para o desenvolvimento do efeito protetor de S. boulardii

Protective effect of the probiotic Lactobacillus acidophilus ATCC 4356 in BALB/c mice infected with Toxocara canis

Human toxocariasis consists of chronic tissue parasitosis that is difficult to treat and control. This study aimed to evaluate the action of the probiotic Lactobacillus acidophilus ATCC 4356 on larvae of Toxocara canis and the effect of IFN-γ cytokine on parasite-host in vivo (1.109 CFU) and in vitro (1.106, 1.107, 1.108, 1.109 CFU) interactions. Four groups of six BALB/c mice were formed: G1 - L. acidophilus supplementation and T. canis infection; G2 - T. canis infection; G3 - L. acidophilus supplementation; and G4 - PBS administration. Mice were intragastrically suplemented with probiotics for 15 days before inoculation and 48 h after inoculation with 100 T. canis eggs. The inoculation of T. canis was also perfomed intragastrically. The recovery of larvae took place through digestion of liver and lung tissues; the evaluation of IFN-γ gene transcription in leukocytes was performed by qPCR. The in vitro test consisted of incubating the probiotic with T. canis larvae. The supplementation of probiotics produced a reduction of 57.7% (p = 0.025) in the intensity of infection of T. canis larvae in mice, whereas in the in vitro test, there was no larvicidal effect. In addition, a decrease in the IFN-γ gene transcription was observed in both, T. canis-infected and uninfected mice, regardless of whether or not they received supplementation. The probiotic L. acidophilus ATCC 4356 reduced T. canis infection intensity in mice, however, the probiotic did not have a direct effect on larvae, demonstrating the need of interaction with the host for the beneficial effect of the probiotic to occur. Yet, the proinflammatory cytokine IFN-γ did not apparently contributed to the observed beneficial effect of probiotics

Saccharomyces boulardii immunomodulatory effect in mice experimentally infected with Toxocara canis

Human toxocariasis is a zoonotic disease with high prevalence in developing countries and it has been considered one of the most prevalent helminthiasis in Latin America. Probiotics modulate the immune response, which open up a new perspective of their use for prevention and treatment of parasitic diseases. To study the possible mechanisms of action mediated by the probiotic Saccharomyces boulardii, the aim of this study was to evaluate its immunomodulatory effect in Toxocara canis experimentally infected mice. Initially an in vitro test was performed to assess the existence of harmful effect of probiotic on T. canis. Next, was evaluated the modulation of the immune response of Swiss mice supplemented with S. boulardii and experimentally infected by T. canis. To this end the expressions of IL- 12, IL-17, IL-10, IL-4 and IFNγ cytokines in spleen cells from mice at 24 and 48h post- infection were studied by quantitative polymerase chain reaction (qPCR). The results indicate that the probiotic has no direct effect on parasites larvae, suggesting that is necessary the contact of S. boulardii with the intestinal mucosa of the host to the development of its protective effect. Furthermore S. boulardii promoted reduction of approximately 40% of the number of T. canis larvae recovered. Supplementation with S. boulardii modulated by increasing the expression of IL-12 (7 times), IL-17 (42 times) after 24h of infection and IFNγ (43 times), in uninfected mice. Splenic expression modulation of IL-10 was reduced by half in 48h of infection supplemented mice, and the IL-4 expression showed no difference between groups under the studied conditions. Modulation of innate immunity observed in S. boulardii supplemented mice suggests the elevation of IL-12 and IL-17 as one of the mechanisms involved in the resistance by this probiotic to T. canis infection.A toxocaríase humana é uma zoonose negligenciada com alta prevalência em países em desenvolvimento, sendo considerada uma das helmintoses mais prevalentes na América Latina. Probióticos modulam a resposta imune, o que permite uma nova perspectiva de sua utilização na prevenção e no tratamento de doenças parasitárias. Para estudar possíveis mecanismos da ação probiotica mediada por Saccharomyces boulardii, o objetivo deste estudo foi avaliar seu efeito imunomodulador em camundongos experimentalmente infectados por Toxocara canis. Inicialmente foi realizado um teste in vitro para avaliar a existência de ação nociva do probiótico sobre T. canis. A seguir, foi avaliada a modulação da resposta imune de camundongos Swiss suplementados com S. boulardii e infectados experimentalmente por T. canis. Para tal foram estudadas as expressões das citocinas IL-12, IL-17, IL-10, IL-4 e IFNγ em esplenócitos de camundongos com 24 e 48h pós-infecção, pelo método quantitativo da reação em cadeia da polimerase (qPCR). Os resultados obtidos revelam que o probiótico não possui ação direta sobre as larvas do parasito, sugerindo que se faz necessário o contato de S. boulardii com a mucosa intestinal do hospedeiro para o desenvolvimento de seu efeito protetor. Além disso, foi evidenciado que S. boulardii promoveu redução de aproximadamente 40% no número de larvas de T. canis recuperadas. A suplementação com S. boulardii promoveu modulação aumentando a expressão das citocinas IL-12 (7 vezes), IL-17 (42 vezes) após 24h da infecção e IFNγ (43 vezes), nos camundongos não infectados. A modulação da expressão esplênica de IL-10 foi reduzida à metade nos camundongos suplementados após 48h de infecção, e a expressão de IL-4 não mostrou diferença entre os grupos nas condições estudadas. A modulação da imunidade inata, observada em camundongos suplementados com S. boulardii, sugere a elevação da expressão de IL-12 e IL-17 como um dos mecanismos envolvidos por este probiótico na resistência à infecção por T. canis

Immunofluorescent Antibody Test (IFAT) for Trypanosoma cruzi in dogs from urban and rural areas of Pelotas, RS

Chagas disease (CD) is a zoonosis with the protozoan Trypanosoma cruzi as the causative agent. Dogs are considered the main domestic reservoir for T. cruzi in most Latin American countries and in some areas of the United States. In southern Brazil, despite being an endemic area of the disease, the prevalence in dogs is still unknown. This study aimed to evaluate the frequency of T. cruzi antibodies in dogs from urban and rural areas of Pelotas, RS, Brazil. A total of 227 canine sera were used for serological tests, of which 99 were from urban areas and 128 were from rural areas of Pelotas. Information regarding the environment and the possible risk factors (origin, rural contact, age, breed, confinement and gender) to which the dogs were exposed were recorded. Indirect immunofluorescence was used to assess the presence of specific immunoglobulins (IgG) anti-T. cruzi in the serum of dogs. Of the 227 sera analyzed, 81 (35.7%) exhibited anti-T. cruzi, which represented 34.3% of the dogs from the urban area and 36.7% of the dogs from the rural area. Among the variables analyzed, rural contact and male gender showed an association with seropositivity for T. cruzi. The detection of T. cruzi antibodies in the serum of these dogs emphasizes the need to study trypanosomiasis in this important domestic reservoir of Chagas disease.</span

ELEVATED TRANS-MAMMARY TRANSMISSION OF Toxocara canis LARVAE IN BALB/c MICE

A toxocaríase é zoonose amplamente difundida e considerada importante problema de saúde pública. O objetivo deste estudo foi avaliar a frequência da transmissão transmamária de Toxocara canis em camundongos BALB/c neonatos amamentados por fêmeas experimentalmente infectadas com 1.200 ovos logo após o parto. Após 50 dias de idade, foi avaliada a presença de larvas em diferentes órgãos dos neonatos. A infecção por via transmamária foi confirmada em 73,9% dos camundongos amamentados por fêmeas infectadas. Estes dados demonstram elevada transmissão transmamária de T. canis e confirmam a importância desta via de transmissão em hospedeiros paratênicos.Toxocariasis is a widespread zoonosis and is considered an important worldwide public health problem. The aim of this study was to investigate the frequency of trans-mammary Toxocara canis infection in newborn BALB/c mice nursed by females experimentally infected with 1,200 eggs after delivery. After 50 days of age, the presence of larvae in different organs of the offspring was investigated. Trans-mammary infection was confirmed in 73.9% of the mice that had been nursed by infected females. These data show a high trans-mammary transmission of T. canis and confirm the significance of this transmission route in paratenic hosts

Vertical transmission of Toxocara canis in successive generations of mice

Visceral toxocariasis is a neglected zoonosis caused byToxocara canis larvae in unusual hosts. In dogs, the definitive host, the infection occurs mainly through transplacental and transcolostral transmission. Studies on experimental models have shown that vertical transmission may result from acute infections. Considering that toxocariasis is characterized as a chronic infection, with possible reactivation of larvae present in the brain, this study evaluated the presence of larvae in the brain of female BALB/c mice and their offspring with chronic infection during three successive pregnancies. ELISA-TES was used to evaluate the antibody levels. T. canis larvae were detected in the brain tissue of the mice during the three successive generations evaluated. The offspring's IgG level gradually decreased, and mean absorbance (ABS) above the cutoff point (0.070) was observed only at 30 (0.229) and 50 (0.096) days of age, while IgM was not detected. The infections in the offspring confirmed that vertical transmission of T. canis larvae occurred during chronic toxocariasis in three successive generations of mice

The serodiagnostic potential of recombinant proteins TES-30 and TES-120 in an indirect ELISA in the diagnosis of toxocariasis in cattle, horses, and sheep.

Toxocariasis is a zoonotic disease that affects humans and animals alike. Although recombinant proteins are widely used for its diagnosis in humans, their performance in companion and production animals remains unknown. This study aimed to investigate the serodiagnostic potential of the recombinant proteins rTES-30 and rTES-120 from Toxocara canis in an indirect ELISA for cattle, horses, and sheep. Serum samples collected from the animals were tested with indirect ELISA and Western Blotting using T. canis TES-30 and TES-120 recombinant proteins produced in Escherichia coli, as well as native-TES. In the ELISA, rTES-30 showed high serodiagnostic potential in sheep and horses (92.6% and 85.2%, respectively), while the sensitivity of rTES-120 was higher in cattle and horses (97.2% and 92.6%, respectively). Furthermore, a highly positive association was observed between native and recombinant proteins in seropositive samples, while a moderately positive association was observed in seronegative samples, probably due to the lower specificity of native TES. In conclusion, our study indicates that the use of recombinant proteins in an indirect ELISA is an effective tool for the serodiagnosis of toxocariasis in animals, with the choice of protein being species-dependent