Occurrence of anti-Toxoplasma gondii antibodies and risk factors associated with infection in equids slaughtered for human consumption in Brazil

Humane Endpoints in Swiss Webster Mice Infected with Toxoplasma gondii RH Strain

The highly virulent Toxoplasma gondii RH strain is maintained through successive passages in mice, but there is still a lack of studies that refine these procedures from a 3Rs perspective, where humanitarian ideals aim to minimize the stress, pain, or suffering of the animals used in the research without the loss of results. The aim of this study was to establish humane endpoints in Swiss Webster mice inoculated with the T. gondii RH strain. A total of 52 mice were infected with 5 × 106 tachyzoites/mL and monitored for periods of up to 5 days. The parameters body weight; hair condition; higher than normal body temperature; hypothermia; respiratory function; pain; soft stools or diarrhea; bloody diarrhea; tense, nervous, or in distress during handling; and ascites were recorded daily in score tables. The results showed that prominent piloerection, respiratory function, pain parameters, and ascites are important clinical signs to be used as a cut-off point for implementing euthanasia. The application of this refinement method helped to avoid animal suffering and pain without compromising the number of parasites recovered. We therefore suggest adopting these parameters in research protocols that require the maintenance of the T. gondii RH strain in murine models to avoid and reduce animal suffering.

Serological Evidence of Hepatitis E Virus Infection in Brazilian Equines

Hepatitis E virus (HEV) infection has been demonstrated in various animal species; those recognized as potential zoonotic reservoirs pose a considerable risk to public health. In Brazil, HEV-3 is the only genotype identified in humans and swine nationwide, in a colony-breeding cynomolgus monkey and, recently, in bovines and capybara. There is no information regarding HEV exposure in the equine population in Brazil. This study aimed to investigate anti-HEV antibodies and viral RNA in serum samples from horses slaughtered for meat export and those bred for sport/reproduction purposes. We used a commercially available ELISA kit modified to detect species-specific anti-HEV, using an anti-horse IgG-peroxidase conjugate and evaluating different cutoff formulas and assay precision. Serum samples (n = 257) were tested for anti-HEV IgG and HEV RNA by nested RT-PCR and RT-qPCR. The overall anti-HEV seroprevalence was 26.5% (68/257) without the detection of HEV RNA. Most municipalities (53.3%) and farms (58.8%) had positive horses. Animals slaughtered for human consumption had higher risk of HEV exposure (45.5%) than those bred for sports or reproduction (6.4%) (p < 0.0001). The statistical analysis revealed sex and breeding system as possible risk-associated factors. The first serological evidence of HEV circulation in Brazilian equines reinforces the need for the surveillance of HEV host expansion in a one-health approach.

Seroprevalence and associated risk factors of Toxoplasma gondii infection among slaughterhouse workers in Yangon Region, Myanmar: A cross-sectional study

BACKGROUND

Toxoplasmosis, having the significant consequences affecting mortality and quality of life, is still prevalent in various places throughout the world. The major gap in surveillance for Toxoplasma gondii infection among high-risk population, slaughterhouse workers, is an obstacle for the effective policies formulation to reduce the burden of toxoplasmosis in Myanmar. Therefore, this study aimed to assess the seroprevalence of toxoplasmosis and associated factors of seropositivity among slaughterhouse workers in Yangon Region, Myanmar.

METHODS

A cross-sectional study that was conducted from June to November 2020 included 139 slaughterhouse workers involving at five main slaughterhouses under Yangon City Development Committee, Myanmar. The presence of IgG and IgM anti-T. gondii antibodies in serum was detected using the OnSite Toxo IgG/IgM Combo Rapid Test. A face-to-face interview was also performed using pretested structured questionnaires to obtain the detail histories: sociodemographic characteristics, level of knowledge, occupational factors, and environmental factors related to T. gondii infection. Bivariate logistic regression was used to determine the factors associated with T. gondii infection.

RESULTS

Of all participants, the overall seroprevalence of anti-T. gondii was 43.9% (95% CI: 35.5-52.5%), of whom 98.4% (95% CI: 91.2-100.0%) were reactive only for IgG antibody and 1.6% (95% CI: 0.0-8.8%) were reactive for IgG and IgM antibodies. The significant factors associated with the seropositivity of T. gondii antibodies were blood transfusion history (OR: 5.74, 95% CI: 1.17-28.09), low level of knowledge (OR: 2.91, 95% CI: 1.46-5.83), contact with animal organs, muscles or blood (OR: 14.29, 95% CI: 1.83-111.51), and animals most frequently slaughtered (cattle) (OR: 3.22, 95% CI: 1.16-8.93).

CONCLUSIONS

A high seroprevalence of toxoplasmosis was detected among slaughterhouse workers in Yangon Region and it raises a significant public health concern. Therefore, providing health education regarding toxoplasmosis, enforcement of personal hygiene practices in workplaces, the establishment of training for occupational hygiene, and commencement of the risk assessment and serological screening for toxoplasmosis are crucial to curtail the prevalence of T. gondii infection among slaughterhouse workers.

A Systematic Review and Meta-Analysis on the Occurrence of Toxoplasmosis in Animals Slaughtered in Brazilian Abattoirs

Toxoplasmosis is mainly transmitted to human beings through the consumption of contaminated food, and several outbreaks caused by infected meat consumption have been reported in Brazil. We performed a systematic literature review on the prevalence and risk factors for toxoplasmosis in slaughtered animals and performed a meta-analysis of its prevalence for different species and regions. Furthermore, we also discussed the infectivity of seropositive animals, risk factors, and preventive strategies. In the meta-analysis, the overall prevalence estimates for poultry, ostrich, goats, swine, equids, sheep, and bovines were 42.4, 40.4, 23.0, 19.9, 19.1, 17.3, and 16.2%, respectively. Regarding the Brazilian regions, the highest prevalence values were detected for bovines and equids in the South (32.3 and 34.4%, respectively) and swine, goats, sheep, and poultry in the Northeast (29.3, 23.0, 22.9, and 69.8%%, respectively). High proportions of Toxoplasma gondii viability in bioassay conducted on seropositive animals were seen for sheep (34/40 = 85%) and swine (12/15 = 80%). Toxoplasma gondii infections are widespread on Brazilian farms, and the summarized data allow the establishment of high-priority areas and/or species for the adoption of preventive strategies to control this parasite at different levels of the food chain.

Invited review: Sarcocystis neurona, Neospora spp. and Toxoplasma gondii infections in horses and equine protozoal myeloencephalitis (EPM): five decades of personal experience, perspectives, and update

Sarcocystis neurona, Neospora spp. and Toxoplasma gondii are related protozoans; they were considered the same parasite until 1970s. Two of these parasites, S. neurona and Neospora spp. are associated with a neurological syndrome in horses, called equine protozoal myeloencephalitis (EPM). The diagnosis and treatment of EPM are difficult. Most cases of EPM are related to S. neurona while only a few are due to Neospora spp. infections. There are two species of Neospora, Neospora caninum that has a wide host range and Neospora hughesi that has been found only in horses. Currently, T. gondii is not considered as a cause of EPM in horses, although it causes neurological illness in many other hosts, including humans. The present review provides an update on history, life cycle, diagnosis and treatment of these three infections in horses.

Occurrence of serum antibodies to Toxoplasma gondii and associated risk factors in donkeys from central Kenya

Toxoplasma gondii is an intracellular parasite of zoonotic concern and economic importance in humans and animals, respectively. This study was conducted to determine the occurrence of T. gondii and associated risk factors in domestic donkeys from Kirinyaga and Meru counties in Kenya. Blood samples were collected from 363 randomly selected donkeys for detection of antibodies to T. gondii using a commercial kit ID Screen® Toxoplasmosis Multi-species indirect enzyme-linked immunosorbent assay (ELISA). The data on risk factors were collected by interviewing donkey owners using epidemiological questionnaire. Serum antibodies to T. gondii were detected in 26.4% (95% CI: 22.2-31.3) of the donkeys. The analysis showed that age of donkeys (OR = 2.484, 95% CI: 1.315-4.693; p = 0.005) was associated with increased risk for T. gondii seroprevalence while county of origin of donkeys (OR = 0.182, 95% CI: 0.083-0.400; p = 0.000), residential place of donkeys (OR = 0.301, 95% CI: 0.136-0.665; p = 0.003), rearing chicken (OR = 0.203, 95% CI: 0.064-0.644; p = 0.007), and donkey production system (OR = 0.644, 95% CI: 0.456-0.909; p = 0.012) were associated with reduced risk of T. gondii seroprevalence. This is the first report to provide epidemiological information on T. gondii infection among donkeys in Kenya. The presence of antibodies to T. gondii in donkeys suggests the high potential of transmission to other animals and humans. Regular monitoring and control of T. gondii infection in donkeys were recommended in the study area.