Serosurvey of anti-Leishmania (Leishmania) infantum antibodies in hunting dogs and hunters in Brazil.

BACKGROUND AND AIM: Although wild boar hunting activities and the hunting dog trade in the Atlantic Forest and Cerrado biomes of Brazil overlap both with endemic and with non-endemic areas for visceral leishmaniasis, no study to date has focused on Leishmania spp. exposure among hunting dogs and hunters. The aim of the present study was to assess the presence of Leishmania spp. antibodies in hunting dogs and hunters in different anthropized areas of two Brazilian biomes. MATERIALS AND METHODS: Blood samples were collected from 170 hunting dogs and 46 hunters between October 2016 and May 2018. The presence of antibodies against Leishmania spp. in hunting dogs was screened through a dual-path platform immunochromatographic test (DPP rapid test; Bio-Manguinhos/Fundação Oswaldo Cruz, Rio de Janeiro, Brazil) and in hunters through an rK39-based rapid immunochromatographic test. Both tests were used in accordance with Brazilian Ministry of Health recommendations. RESULTS: Overall, although antibodies were detected through the immunochromatographic test in 3/170 (0.02%) of these female asymptomatic hunting dogs, all living in anthropized areas of the Atlantic Forest biome in South Brazil, no sample was confirmed through the enzyme-linked immunosorbent assay. All the hunters were non-reactive in the rapid immunochromatographic test. CONCLUSION: Our study on three suspicious hunting dogs has suggested that Leishmania (Leishmania) infantum may circulate both in endemic and non-endemic areas in Brazil. In addition, a high rate of hunting dog replacement due to death and trade may have led to less chance of infection and transmission between animals and between animals and humans, which would corroborate the outcomes reported here. Further studies should be conducted to fully establish whether hunting dogs and hunters may be used as sentinels in other areas endemic for Leishmania spp.

Risk factors associated with ticks and Rickettsia spp. exposure in wild boars (Sus scrofa), hunting dogs, and hunters of Brazil.

BACKGROUND AND AIM: Wild boars have recently been implicated as the maintainers and carriers of Amblyomma spp. ticks, which are essential for Rickettsia spp. transmission. Consequently, wild boar hunting may increase the risk of tick exposure and subsequent human tick-borne infection and disease. Therefore, this study was conducted to evaluate the risk factors for ticks and Rickettsia spp. exposure in wild boars, hunting dogs, and hunters in Brazilian biomes. MATERIALS AND METHODS: The statistical relationship of Rickettsia spp. antibodies were evaluated using the Chi-square test in 80 wild boars, 170 hunting dogs, and 49 hunters. RESULTS: The only statistically significant difference in seropositivity found in this study was between male and female wild boars (p=0.034), probably associated with in-park exposure to Amblyomma brasiliense infected with Rickettsia spp. CONCLUSION: The absence of statistical differences in the associated risk factors for hunting dogs and hunters may indicate a random exposure to Rickettsia spp.

High SARS-CoV-2 seroprevalence in persons experiencing homelessness and shelter workers from a day-shelter in São Paulo, Brazil.

Brazil presents one of the highest COVID-19 death tolls in the world. The initial SARS-CoV-2 epicenter was São Paulo city. As of 2019, the homeless population of São Paulo city was estimated at 24,344 individuals, the largest national homeless population. The present study aimed to concomitantly assess the molecular and serological prevalence and associated risk factors of SARS-CoV-2 infection in a homeless population and related shelter workers from a day-shelter. Serum samples, nasopharyngeal and oropharyngeal swabs of persons who are homeless and shelter workers collected from August 25th to 27th, 2020 were tested for the presence of anti-SARS-CoV-2 IgM and IgG antibodies by ELISA and SARS-CoV-2 RNA by RT-qPCR, respectively. All swab samples tested negative by RT-qPCR. Seropositivity of IgM and IgG was 5/203 (2.5%) and 111/203 (54.7%) in persons who are homeless, and 5/87 (5.7%) and 41/87 (47.1%) in shelter workers, respectively, with no statistical differences between groups. The high seroprevalence found herein indicates early environmental and urban spreading of SARS-CoV-2, associated with sociodemographic and economic vulnerability.

Serosurvey of Eastern, Western, and Venezuelan Equine Encephalitis Viruses in Wild Boars (Sus scrofa), Hunting Dogs, and Hunters of Brazil.

A total of 102 free-range wild boars, 170 hunting dogs, and 49 hunters from 3 Brazilian regions were sampled and tested for antibodies to eastern equine encephalitis virus (EEEV), western equine encephalitis virus, and Venezuelan equine encephalitis virus. Three of the 102 (2.9%) wild boars were positive for antibodies against EEEV by microplate serum neutralization test. Based on our data, free-range wild boars from central-western Brazil may be exposed to EEEV, and further studies are needed to evaluate the potential of incorporating serosurveys in routine arbovirus activity surveillance specifically to identify arbovirus activity foci and to help establish thresholds for epidemic transmission.

Seroprevalence of anti-Toxoplasma gondii antibodies in wild boars (Sus scrofa), hunting dogs, and hunters of Brazil.

Seroprevalence of Toxoplasma gondii has been extensively studied in wild boars worldwide due to the emerging risk for human infection through meat consumption. However, this is the first study that reports toxoplasmosis seroprevalence in wild boars, wild boar hunters and their hunting dogs. The aim of the present study was to evaluate the seroprevalence of anti-T. gondii antibodies in the complex wild boars, hunting dogs and hunters, and to determine the risk factors associated with seropositivity in southern and central-western Brazil. Overall, anti-T. gondii seropositivity was observed in 15/71 (21.1%) wild boars by modified agglutination test (MAT); and 49/157 (31.2%) hunting dogs and 15/49 (32.7%) hunters by indirect immunofluorescent antibody test (IFAT). Seroprevalence of toxoplasmosis in Brazilian wild boars was within the national and international range, posting wild boars as potential environmental sentinels for T. gondii presence. In addition, the findings have comparatively shown that wild boars have been less exposed to infection than hunting dogs or hunters in both Brazilian regions. Seropositivity for T. gondii was statistically higher in 12/14 (85.7%) captured wild boars when compared to 5/57 (7.0%) free-range wild boars (p = 0.000001). Similarly, captured wild boars from anthropized areas were more likely to be seropositive than of natural regions (p = 0.000255). When in multiple regression model, dogs with the habit of wild boar hunting had significant more chance to be positive (adjusted-OR 4.62 CI 95% 1.16-18.42). Despite potential as sentinels of environmental toxoplasmosis, seroprevalence in wild boars alone may provide a biased basis for public health concerns; thus, hunters and hunting dogs should be always be included in such studies. Although hunters should be aware of potential T. gondii infection, wild boars from natural and agricultural areas may present lower protozoa load when compared to wild boars from anthropized areas, likely by the higher presence of domestic cats as definitive hosts.