Detection of ectoparasites and investigation of infection by Rickettsia spp. and Trypanosoma spp. in bats from Rio Grande do Sul, Brazil.

This study aimed to investigate the presence of ectoparasites and the occurrence of natural infection by Rickettsia spp. and Trypanosoma spp. in bats from Rio Grande do Sul (RS), Brazil. The evaluated animals were obtained from the Instituto de Pesquisas Veterinárias Desidério Finamor, sent by the Centro Estadual de Vigilância Sanitária, to carry out rabies diagnostic tests, during the period from 2016 to 2021. The bats came from 34 municipalities in RS. Of the 109 animals surveyed, 35.8% (39/109) had 385 ectoparasites, with an average of 9.9 parasites per animal. Of these bats, all had insectivorous feeding habits, with 35.9% (14/39) females and 64.1% (25/39) males. The co-parasitism of Chirnyssoides sp., Ewingana inaequalis, and Chiroptonyssus robustipes on Molossus currentium (Mammalia, Chiroptera) was recorded for the first time. All bats surveyed were negative for infection by the protozoan and bacteria. Thus, the expansion of the occurrence of these ectoparasites in insectivorous bats in RS was observed. Furthermore, this study corresponds to the first recorded interspecific associations for the species.

Molecular identification of Sarcocystis species in wild boar (Sus scrofa) and pigs (Sus scrofa domesticus) in Brazil.

Sarcocystis spp. are protozoan parasites that form cysts in the organs and musculature of various animal species. The species Sarcocystis miescheriana and Sarcocystis suihominis are pathogenic to pigs and wild boars (Sus scrofa), acting as intermediate hosts, while humans are the definitive host for S. suihominis. To date, there have been no reports of the identification of these coccidian species in Sus scrofa in Brazil. Therefore, in this study, we conducted the first molecular identification of Sarcocystis species using PCR-RFLP and sequencing. A total of 210 samples were analyzed, of this total, 67 tested positive for Sarcocystis spp., representing 31.9% of the total samples assessed. Out of the total positive samples, 55 (82.1%) were identified as S. miescheriana and 8 (11.9%) as S. suihominis, a zoonotic species. Additionally, other species related to bovines, such as S. cruzi and zoonotic S. hominis, were detected in 3.0% of the samples, serving as contaminants in the pork products. The presence of S. suihominis in swine and wild boar samples is concerning due to the zoonotic risk and potential environmental contamination, as humans act as definitive hosts, also for the presence of S. hominis as a bovine contaminant in pork sausages. Furthermore, we confirmed the efficacy of the PCR-RFLP technique as a reliable tool for the identification of Sarcocystis species, demonstrating its potential use in laboratories for molecular diagnosis and rapid identification of these parasites, aiming to protect public health and ensure food safety.

Molecular identification of Sarcocystis neurona in tissues of wild boars (Sus scrofa) in the border region between Brazil and Uruguay.

Sarcocystis neurona, owing to its clinical importance in domestic animals, is currently one of the most studied agents, presenting a wide range of intermediate hosts that have not yet been described, mainly in wild fauna. Thus, the aim of this study was to describe the detection and molecular detection of S. neurona by amplification of the 18S rRNA region in the tissues of wild boars killed by boar control program in border Brazil Uruguay. A total of 79 samples of DNA from wild boar tissues from the LADOPAR/UFSM sampling bank were used, with Nested-PCR reactions being performed for amplification of the 18S rRNA region and the expected final product of 290 bp. Subsequently, the positive samples were subjected to restriction fragment length polymorphism (RFLP) technique with the restriction enzymes DdeI and HPAII. A second semi-Nested reaction was performed to obtain a larger sequence of nucleotides with amplification of the 18S region and the expected final product of 500 bp for S. neurona and Nested amplification ITS1 with product final of 367 pb. In 32 samples, it was possible to detect S. neurona both by nested Nested-PCR reaction and RFLP, and the presence of the agent was confirmed by sequencing, corresponding to 40.51% of the total tissues evaluated. This is the first report of the occurrence of this species of Sarcocystis in wild boars, and further studies evaluating the role of these animals as intermediate hosts, and in the epidemiology of this protozoan are necessary, as well as verifying the risk factors for infection.

Antimicrobial activity of cationic water-soluble porphyrin against multidrug-resistant bacteria in biofilms and canine skin samples.

Multidrug-resistant (MDR) microorganisms pose a threat to animal health, particularly in integumentary diseases, which can be caused by multiple organisms and often manifest as biofilms, hindering treatment effectiveness. We evaluated the antimicrobial activity of antimicrobial photodynamic therapy (aPDT) using a water-soluble tetra-cationic porphyrin (4-H2TMeP) against MDR bacteria cultured in biofilm and in mono and polyculture grown on canine skin samples. We utilized 4-H2TMeP porphyrin against MDR Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus pseudintermedius. A non-cytotoxic concentration of 4-H2TMeP (40 µM), previously shown to be effective in vitro against these bacteria cultured in solution, was employed. Biofilms were treated with 4-H2TMeP and subjected to light irradiation for 30, 60, and 90 min. Monocultures on canine skin samples were treated with 4-H2TMeP and irradiated for 30 (S. pseudintermedius), 60 (E. coli), or 60 and 90 min (P. aeruginosa). Polycultures of S. pseudintermedius and E. coli were treated with light for 60 and 90 min. The efficacy of aPDT was evaluated by plating light-exposed biofilms, mono and polycultures of bacteria obtained from skin samples exposed to light and kept in the dark. Colony-forming units were counted after 24 h of incubation at 37 °C. aPDT using 4-H2TMeP reduced bacterial concentrations of S. pseudintermedius and E. coli biofilms. Additionally, it significantly reduced bacterial concentrations cultivated on skin samples, with a particular emphasis on S. pseudintermedius. These findings indicate that aPDT with 4-H2TMeP is a promising alternative treatment against MDR bacteria in animal skin infections and should be further explored through in vivo research.

Economic losses caused by mastitis and the influence of climate variation on the occurrence of the disease in a dairy cattle farm in southern Brazil.

This study evaluated the economic impacts caused by mastitis in a small dairy farm with similar characteristics and production to most dairy farms in southern Brazil and investigated if climatic variations influenced mastitis occurrence in the region. A farm with, on average, 45 lactating Holstein cattle was monitored from November 2021 to October 2022, and data on mastitis cases, bulk tank milk somatic cell count, animal treatment costs, milk production, animal disposal costs, and production losses were collected. Monthly averages of temperature, relative humidity (RH), and rainfall in the region were obtained. The greatest loss was related to the drop in milk production, resulting in 63.8% of total losses, followed by animal disposal (29.5%), milk disposal (4.6%), and treating animals with mastitis (2.0%), totaling a 10.6% reduction in the annual gross income. There were negative correlations between the clinical mastitis rate and monthly RH and between subclinical mastitis and temperature; the occurrence of subclinical mastitis and average RH were positively correlated. Our findings showed that mastitis negatively impacted the economy and that climate influenced mastitis occurrence.

Molecular detection of DNA from Trypanosoma spp. and Leishmania spp. in wild boar (Sus scrofa) tissues.

Due to the proximity of humans to the countryside and the progressive increase in populations of invasive species, such as wild boars (Sus scrofa), the risk of disease spread is also exacerbated, some of which are zoonoses caused by protozoa. In the present study, 75 tissue/organ samples from 25 wild boars obtained from authorized hunting in the northern region of Rio Grande do Sul were evaluated to investigate the presence of Trypanosoma spp. using conventional PCR with specific primers and amplification of the ITS1 region for Leishmania spp. detection and species differentiation, multiplex PCR with kDNA minicircle amplification was performed. Trypanosoma spp. DNA was detected in 11 out of 25 hearts, representing 44% of the culled animals. Regarding the detection of Leishmania DNA, L. infantum was detected in one spleen sample, accounting for 4%, and L. amazonensis in one liver sample from the same animal, also representing 4% (1/25) of the samples. It is important to note that this wild boar, with detection for both L. amazonensis and L. infantum, also had Trypanosoma spp. DNA detected in a heart sample, indicating the potential of this species to have multiple infections with these agents. Furthermore, this is the first reported case of multiple infection in a wild boar with these agents. Therefore, the results obtained reinforce the risk posed by invasive species, especially wild boars, as potential sources of infectious agent dissemination and their role as possible reservoirs for numerous diseases.

Toxoplasmosis outbreak caused by north American genotypes in captive black-tufted marmosets in southern Brazil.

In this study, we describe an outbreak of toxoplasmosis in an enclosure of five Callithrix penicillata in Southern Brazil. The marmosets were found dead and submitted to necropsy and histopathology. Liver, spleen, and lungs were frozen and sent for polymerase chain reaction (PCR) and nested-PCR-restriction fragment length polymorphism (RFLP) genotyping of Toxoplasma gondii. Necropsy revealed a liver with a lobular pattern, along with diffusely congested lungs, spleen, and kidneys, and hemorrhage in the mesenteric lymph nodes. Mild-to-moderate, multifocal, necrotic hepatitis and splenitis, multifocal lymphoplasmacytic myocarditis, and moderate, diffuse necrohemorrhagic lymphadenitis were observed. T. gondii tachyzoites were in all the organs mentioned. The detected strains were closely related with the isolates TgWtdUs10, TgSoUs39, and TgShUs2, which were originally found in non-primate species all in the United States of America. This is an unprecedented report of North American strains causing mortality in captive individuals of the species Callithrix penicillata in the Southern Brazil.

Sarcocystis in horses from Rio Grande do Sul, Brazil: Molecular identification of Sarcocystis bertrami and Sarcocystis neurona in muscle tissues.

Horses are intermediate hosts of Sarcocystis spp. capable of forming cysts in their musculature. This study aimed to detect sarcocysts and investigate the presence of nucleic acids from Sarcocystis spp. in samples of striated muscles from horses in the State of Rio Grande do Sul, Brazil, necropsied at the Veterinary Pathology Laboratory of the Federal University of Santa Maria. A total of 108 samples were collected from 24 horses and examined through direct examination. Microscopic tissue cysts were observed in three samples: tongue (2) and esophagus (1) from two animals. Extractions were performed on the found cysts and tissues, even though sarcocystosis detection was not present. DNA samples were subjected to Nested-PCR using Tg18s primers, and the amplified products were subjected to Restriction Fragment Length Polymorphism (RFLP) using DdeI and HpaII enzymes. DNA belonging to Sarcocystis spp. was amplified in tissues from 91.7% (22/24) of the equines, and 67.6% (73/108) of the samples tested positive in the Nested-PCR reaction. The tissues with the highest detection frequency were: diaphragm 92.3% (12/13), gluteal muscle 77.2% (17/22), and esophagus 66.7% (4/6). In RFLP, Sarcocystis spp. was detected in 21 tissues from 11/22 equines, and cysts, identified through nucleotide sequencing, were determined to be S. bertrami. S. neurona was identified in 11 samples from 7/22 animals, with co-infection detected in 5/22 cases. The high detection rate indicates a concerning circulation of the protozoan, particularly the zoonotic S. bertrami found in all tissues, which are commonly exported for human consumption.

Detection of anti-Leishmania spp. antibodies in poultry from central region of Rio Grande do Sul, Brazil.

Domestic birds such as Gallus gallus, Meleagris gallopavo, Anser anser and Numida meleagris are widely distributed throughout the world and maintain contact with humans and other animal species considered reservoirs of both Visceral Leishmaniasis (VL) and American Tegumentary Leishmaniasis (ATL), including dogs and cats; wild canids, marsupials; and synanthropic animals such as rodents and chiroptera. Therefore, this study aimed to detect the presence of anti-Leishmania spp. antibodies in birds from a rural area of the municipality of Santa Maria, southern Brazil. From May to December 2022, 262 blood samples were collected from 244 chickens, 8 turkeys, 7 guinea fowl and 3 geese, distributed in 27 rural properties in 6 districts. All the sites visited presented positive birds for the presence of Leishmania spp. Thus, it is inferred that, contact with this protozoan can induce the production of antibodies, suggesting that these animals can be used as sentinels for the circulation of this agent. In addition, the blood of these animals is a preferred food source for insects of the subfamily Phlebotominae, which can be used them as bioindicators of the presence of these phlebotomes.

Detection of anti-Trypanosoma spp. antibodies in cattle from southern Brazil.

Bovine trypanosomosis, caused by Trypanosoma vivax, is a disease that originated in Africa and currently affects cattle in several South American countries, including almost all Brazilian states. Despite the reports on T. vivax infection in southern Brazil, data on its circulation status is currently unavailable. In this study, we aimed to detect anti-Trypanosoma spp. IgG antibodies in cattle from Rio Grande do Sul and suggest areas with T. vivax transmission risk. A total of 691 serum samples from cattle in the intermediate regions of Rio Grande do Sul were analyzed using indirect immunofluorescence assay (IFA). The overall seroprevalence of anti-Trypanosoma antibodies in cattle was 24.6% (170/691). The detection rate ranged from 0-37.3%, with a high prevalence in the intermediate regions of Ijuí (37.3%), Uruguaiana (30.7%), and Passo Fundo (28.9%). Thus, these regions were suggested as possible bovine trypanosomosis risk areas due to the high seroprevalence. This is the first serological study to determine Trypanosoma spp. infection status in cattle from Rio Grande do Sul, providing data on the epidemiology of trypanosomosis in the state.

Increased frequency of detection of anti-Toxoplasma gondii antibodies in domestic cats after outbreak of human toxoplasmosis.

Toxoplasmosis affects various organisms, including humans. In 2018, the largest outbreak of human toxoplasmosis described so far was reported in southern Brazil, with 809 human cases reported, and water as the potentially primary source of infection. Therefore, in this study, we aimed to evaluate the seroprevalence of Toxoplasma gondii in naturally infected domestic cats before and after the human toxoplasmosis outbreak, as well as the potential for environmental contamination by the number of cats infected after the outbreak. We evaluated 381 serum samples from domestic cats in southern Brazil, using an indirect immunofluorescence assay, with samples considered positive at a titer of 1:20. We found that 73% (204/279) and 27% (75/279) of the samples analyzed before the outbreak were negative and positive, respectively. After the outbreak, 62% (69/112) were negative of the samples were and 38% (43/112) were positive. Notably, the proportion of positive samples before the outbreak before (27%) was significantly lower than that after the outbreak (38%; P = 0.020). Therefore, the increased seroprevalence of T. gondii in cats was probably correlated with the ingestion of contaminated water. Therefore, it is important to monitor animals, mainly definitive hosts, after toxoplasmosis outbreaks, considering that these animals can contaminate the environment and, consequently, humans.

Five years of the biggest outbreak of human toxoplasmosis in Santa Maria, Brazil: a review.

Toxoplasmosis is a parasitic disease caused by infection with the protozoan Toxoplasma gondii. In 2018, the first cases of people with clinical signs of acute febrile syndrome were reported, and in the same year, the largest outbreak of human toxoplasmosis ever described in the literature was reported. In this sense, the present work sought to describe the evolution of the outbreak cases in the municipality of Santa Maria, Rio Grande do Sul State, Brazil, as well as the studies conducted and published during and after the outbreak in the municipality (the period between 2018 and 2023). In addition, the discussion of public policies and their modifications after the notification of this outbreak. As a result of this research, verifying the evolution of notified and confirmed cases, the possibility of detection and genotypic characterization of T. gondii and the possibility of co-infections and evaluation of the humoral response is possible. With regard to public policies, the importance of detecting the agent through the heel prick test and increasing the monitoring of water quality to prevent outbreaks.

Anti-Leishmania spp. antibody detection in domestic cats from a visceral leishmaniasis transmission area.

Feline leishmanial infection is reported worldwide, but the epidemiological role of domestic cats in the leishmaniasis cycle remains unclear, and cats might act as cryptic reservoir hosts in endemic areas with no feline leishmaniosis cases. Considering that, a serological screening for anti-Leishmania spp. antibodies was performed by indirect immunofluorescence antibody test (IFAT) in 389 necropsied cats' serum samples from a new visceral leishmaniasis transmission area with no feline leishmanial infection reported to unveil if the cats are being exposed to the parasite. The overall seroprevalence for Leishmania spp. was 11.05% (43/389). No association was found between sex, neutering status, age group, breed, coat length, feline immunodeficiency virus (FIV) infection, and Leishmania spp. antibody detection. A positive association was found with coat color (cats within the orange spectrum with white [particolor]) (OR = 2.47, CI 95% 1 - 6.13, P = 0.044) and a negative association (OR = 0.38, CI 95% 0.18 - 0.79, P = 0.01) between feline leukemia virus (FeLV) infection and IFAT positivity for Leishmania spp. Therefore, it is concluded that the seroprevalence found was greater than 10%, indicating contact of the protozoan with cats in the region served.

Efficacy Evaluation of a Commercial Formulation With Duddingtonia Flagrans in Equine Gastrointestinal Nematodes.

The indiscriminate use of antiparasitics for the treatment of helminths in horses has caused the ineffectiveness of commonly used chemical active principles, therefore, new alternatives such as the use of helminthophagous fungi have been studied. In this context, this study aimed to evaluate the in vitro efficacy of the commercial formulation Bioverm, composed of the fungus Duddingtonia flagrans strain AC001, in the reduction of gastrointestinal nematode larvae in equine feces. In coproculture, the genus Cyathostomum sp. was the most prevalent in the analyzed samples. The commercial formulation with D. flagrans demonstrated effectiveness in the predation of Cyathostomum sp. in tests. The recommended dose of 0.4 g, containing 105 chlamydospores per gram of product, reduced larvae by 44.23%, while the extrapolated dose of 1.0 g with the same concentrations of chlamydospores (105/g) resulted in a reduction of 57.20%, indicating the effectiveness of the product in controlling infective larvae.

Molecular detection of Toxoplasma gondii, Neospora caninum and Sarcocystis spp in tissues of Sus scrofa slaughtered in southern Brazil.

The aim of this study was to determine the presence of deoxyribonucleic acid (DNA) from Toxoplasma gondii, Sarcocystis spp. and Neospora caninum, in tissues of wild boars slaughtered in southern Brazil. A total of 156 samples were collected from different organs of 25 wild boars, and DNA from at least one of the protozoa investigated was detected in 79 samples. To differentiate between infectious agents, restriction fragment length polymorphism was performed using the restriction enzymes DdeI and HpaII. For N. caninum, conventional PCR was performed with specific primers. The DNA of at least one of the studied pathogens was detected in each animal: 26.58% for T. gondii, 68.36% for Sarcocystis spp. and 5.06% for N. caninum. Coinfection between T. gondii and Sarcocystis spp. occurred in 14 animals, between T. gondii and N. caninum in only one male animal, between Sarcocystis spp. and N. caninum in a female, while co-infection with the three agents was equally observed in only one male animal. Considering the high frequency of detection and its zoonotic risk, especially T. gondii, it appears that wild boars can be potential sources of transmission of infectious agents and the adoption of monitoring measures in these populations should be prioritized.

Identification of infection by Leishmania spp. in wild and domestic animals in Brazil: a systematic review with meta-analysis (2001-2021).

Leishmaniasis is a zoonosis caused by protozoan species of the genus Leishmania. It generates different clinical manifestations in humans and animals, and it infects multiple hosts. Leishmania parasites are transmitted by sandfly vectors. The main objective of this systematic review was to identify the host, or reservoir animal species, of Leishmania spp., with the exception of domestic dogs, that were recorded in Brazil. This review included identification of diagnostic methods, and the species of protozoan circulating in the country. For this purpose, a literature search was conducted across index journals. This study covered the period from 2001 to 2021, and 124 studies were selected. Eleven orders possible hosts were identified, including 229 mammalian species. Perissodactyla had the highest number of infected individuals (30.69%, 925/3014), with the highest occurrence in horses. In Brazil, the most commonly infected species were found to be: horses, domestic cats, rodents, and marsupials. Bats, that were infected by one or more protozoan species, were identified as potential reservoirs of Leishmania spp. Molecular tests were the most commonly used diagnostic methods (94 studies). Many studies have detected Leishmania spp. (n = 1422): Leishmania (Leishmania) infantum (n = 705), Leishmania (Viannia) braziliensis (n = 319), and Leishmania (Leishmania) amazonensis (n = 141). Recognizing the species of animals involved in the epidemiology and biological cycle of the protozoan is important, as this allows for the identification of environmental biomarkers, knowledge of Leishmania species can improve the control zoonotic leishmaniasis.

Production performance and economic analysis of broiler chickens after vaccination with a live attenuated vaccine against avian coccidiosis.

The objective of this study was to evaluate the effectiveness of live attenuated commercial vaccine LIVACOX® T against avian coccidiosis upon parasite exposure through its correlation with productive and economic performance, clinical observation, and oocyst excretion of broiler chickens. For this purpose, 420 1-day-old Cobb chicks were divided into five groups of 84 birds: (G1) unvaccinated and unchallenged control; (G2) vaccinated on day 0; (G3) challenged on day 1; (G4) vaccinated on day 0 and challenged on day 14; and (G5) challenged on day 14. For 28 days, the clinical signs of infection, weight and feed conversion of the birds, and excretion of oocysts in the feces were evaluated. Macroscopic analysis of intestinal lesions in birds was also performed. After vaccination in G2, G3, and G4 as well as after challenge in G3, G4, and G5, there was an increase in oocyst excretion. In the analysis of weight gain, the difference in final weight between groups G3 and G4 is - 105.74 g per bird. Therefore, if we multiply this value by the average number of birds slaughtered per day in a medium/large slaughterhouse (250,000), we have 26,435 kg of chicken meat per day of slaughter, representing 581,570 kg of monthly losses (22 days of slaughter/month), or approximately R$3,489,420.00 (US$872,355.00), considering the commercial value at R$6.00/kg (US$ 1.5/kg). Thus, the productive and economic impact of coccidiosis in broiler chickens is evident, and the importance of vaccination to prevent the occurrence of the disease and reduce subsequent loss is highlighted.

Antibiofilm action using water-soluble tetra-cationic porphyrin and antibacterial photodynamic therapy against Moraxella spp. from cattle.

Infectious bovine keratoconjunctivitis (IBK) is the most important eye disease in ruminants worldwide. Moraxella bovis and Moraxella bovoculi can form biofilm and are frequently isolated from affected animals. Antimicrobials are used worldwide to treat clinical cases of IBK, although they have limited success in clearing the infection. Therefore, photodynamic therapy using porphyrins as photosensitizing molecules is an alternative method to eliminate microorganisms, including biofilms. We evaluated the antibacterial activity of a zinc(II) metalloporphyrin (ZnTMeP) against M. bovis and M. bovoculi biofilms since this compound can efficiently inactivate planktonic Moraxella spp. This study was carried out with two reference strains of Moraxella spp. (M. bovis: ATCC® 10900 and M. bovoculli: ATCC® BAA1259). The antibacterial activity of 4.0 µM of the ZnTMeP porphyrin was evaluated on forming and consolidate biofilms with three 30-min cycles of white-light exposure for three days. The ZnTMeP porphyrin reduced M. bovis and M. bovoculi biofilm formation. In addition, ZnTMeP partially destroyed consolidated M. bovoculi biofilms in the second white-light irradiation cycle, although the porphyrin had no effect against the consolidated biofilm of M. bovis. Despite the biofilm still not being completely inactivated, our findings are promising and encourage further experiments using the phototherapy protocol.

Zinc and Manganese Imbalances in BALB/c Mice Experimentally Infected with Leishmania (Leishmania) amazonensis.

PURPOSE: The clinical progression of Leishmania (Leishmania) amazonensis infection depends on multiple factors, including immunological status of the host and their genotypic interaction. Several immunological processes depend directly on minerals for an efficient performance. Therefore, this study used an experimental model to investigate the alterations of trace metals in L. amazonensis infection associate with clinical outcome, parasite load, and histopathological lesions, and the effect of CD4 + T cells depletion on these parameters. METHODS: A total of 28 BALB/c mice were divided into 4 groups: 1-non-infected; 2-treated with anti-CD4 antibody; 3-infected with L. amazonensis; and 4-treated with anti-CD4 antibody and infected with L. amazonensis. After 24 weeks post-infection, levels of calcium (Ca), iron (Fe), magnesium (Mg), manganese (Mn), Cu, and Zn were determined by inductively coupled plasma optical emission spectroscopy using tissue samples of the spleen, liver, and kidneys. Additionally, parasite burdens were determined in the infected footpad (inoculation site) and samples of inguinal lymph node, spleen, liver, and kidneys were submitted to histopathological analysis. RESULTS: Despite no significant difference was observed between groups 3 and 4, L. amazonensis-infected mice had a significant reduction of Zn (65.68-68.32%) and Mn (65.98 to 82.17%) levels. Presence of L. amazonensis amastigotes was also detected in the inguinal lymph node, spleen, and liver samples in all infected animals. CONCLUSION: The results showed that significant alterations in micro-elements levels occur in BALB/c mice experimentally infected with L. amazonensis and may increase the susceptibility of individuals to the infection.

Increased seroprevalence of anti-Toxoplasma gondii antibodies in dogs in southern Brazil after an outbreak of human toxoplasmosis.

Toxoplasmosis is a worldwide disease caused by Toxoplasma gondii, which can infect diverse hosts, including dogs. Although T. gondii infection in dogs is usually subclinical, they are susceptible to infection and develop a specific immune response to the parasite. In 2018, the largest outbreak of human toxoplasmosis in the world occurred in Santa Maria, in southern Brazil; however, the impact of this outbreak on other hosts was not investigated at the time. Considering that dogs often share the same environmental sources of infection as humans, mainly water sources, and that in Brazil, the detection rates of anti-T. gondii immunoglobulin G (IgG) in dogs is very high, this study investigated the frequency of anti-T. gondii IgG in dogs in Santa Maria before and after the outbreak. A total of 2.245 serum samples were analyzed, 1159 collected before the outbreak and 1086 collected after the outbreak. Serum samples were tested for anti-T. gondii antibodies using an indirect immunofluorescence antibody test (IFAT). The infection detection of T. gondii was 16% (185/1159) before the outbreak and 43% (466/1086) after the outbreak. These results showed the infection of dogs with T. gondii and the high frequency of anti-T. gondii antibodies in dogs after the outbreak in humans in 2018, reinforcing water as a possible source of infection and the importance of including toxoplasmosis in the differential diagnosis of dogs.