Seroprevalence and spatial distribution of Toxoplasma gondii infection in cats, dogs, pigs and equines of the Fernando de Noronha Island, Brazil

The Wildcat That Lives in Me: A Review on Free-Roaming Cats (Felis catus) in Brazil, Focusing on Research Priorities, Management, and Their Impacts on Cat Welfare

Domestic cats (Felis catus) currently occupy the 38th place in the Global Invasive Species Database. Free-roaming cats potentially have broad-ranging impacts on wildlife, occupying most terrestrial environments globally as house pets, strays, or feral animals. In Australia, for example, cats are responsible for the decline in many vertebrate populations and extinction of several native mammals. However, in Brazil, few studies have explored either direct impacts of predation on wildlife, or other indirect impacts, such as competition for resources, niche overlap, hybridization, and disease transmission. In this review, we summarize and discuss 34 original research reports, published between 2001 and 2020, on impacts of free-roaming cats in Brazil. We briefly contextualize the history of cat domestication and present that, in Brazil, more studies have focused on the potential of free-roaming cats to transmit disease than to exert impacts via predation or competition on wildlife. More studies were conducted in Brazilian mainland areas (n = 23)-notably in Atlantic Forest-than on islands (n = 11). The review highlights potential impacts of cats on wildlife. We also discuss how control management strategies can affect the welfare of domestic cats, identifying potential knowledge gaps as well as opportunities for future research. Finally, understanding risks of cat predation is necessary to inform future measures to mitigate impacts on wildlife, without neglecting cat welfare.

Exploring similarities and differences between Toxoplasma gondii and Neospora caninum infections in dogs

Toxoplasma gondii and Neospora caninum infections in dogs are predominantly manifest asymptomatic. However, these infections can also present highly varied and potentially severe clinical signs. This is due to the parasites' ability to replicate in a number of cell types within the host organism, with N. caninum exhibiting a particular tropism for the central and peripheral nervous systems, and T. gondii targeting the central nervous system and musculature. In clinical practice, toxoplasmosis and neosporosis are often considered to be closely related diseases, despite their distinct epidemiological, clinical, diagnostic, and therapeutic characteristics. The present review analyses the similarities and differences between these two protozoan infections, since an accurate and timely aetiological diagnosis is essential for establishing effective therapeutic protocols and control strategies.

Geoepidemiology, seroprevalence and factors associated with Toxoplasma gondii infection in domicilied cats from Paraíba (Brazil)

Toxoplasma gondii is a parasite responsible for toxoplasmosis, an emerging and often neglected zoonosis in South America, particularly Brazil. Felines, the only definitive hosts, excrete oocysts in their feces, potentially infecting all homeotherms. Domestic cats are primarily responsible for contaminating human environments with these oocysts. Monitoring their populations is therefore essential to ensure proper toxoplasmosis prophylaxis. The aim of this study was to estimate the prevalence of T. gondii and exposure factors in a population of owner cats in the city of João Pessoa, Paraíba, Brazil. A total of 267 blood samples were collected from domestic cats aged between 1 and 15 years and tested with an immunofluorescence antibody test. The seroprevalence of antibodies against T. gondii was only 17.22% (46/267 individuals). This result therefore suggests a low contribution of domestic cats to T. gondii contamination of the urban environment. The cats' age and living environment were identified as risk factors for cat exposure to T. gondii.

Risk factors for Toxoplasma gondii infection in dogs: a serological survey

BACKGROUND

Dogs, as well as a wide variety of other warm-blooded animals, act as intermediate host of Toxoplasma gondii. In dogs, most cases of toxoplasmosis are subclinical, although clinical disease has been sporadically reported. Beyond its role in diagnostic pathways, seropositivity also functions as a reflection of the parasite's spread within the dog's living environment. The aim of the present study was to evaluate the possible risk factor associated with seropositivity to T. gondii in dogs in Central-Northern Italy, analysing 120 dogs sera for the presence of IgG antibodies by indirect fluorescence antibody test (IFAT).

RESULTS

The population examined was composed of 54.2% hunting dogs, 24.2% companion dogs, 14.2% truffle dogs and 7.5% watchdogs. Thirty-four (29.2%) dogs tested positive for T. gondii IgG, with titres ranging from 1:40 to 1:1280. Seroprevalence and antibodies titres were not related to dog gender, age or function. The logistic regression and ordered logistic regression results indicated that seroprevalence, and antibody titres were significantly higher in dogs cohabiting with cats, exhibiting coprophagy habits, and living constantly outdoors. Notably, the lifestyle factor showed the highest odds-ratios in the study: dogs living constantly outdoors were found to be at approximately 5 times greater risk of testing positive and having higher antibody titres compared to dogs living both indoors and outdoors.

CONCLUSION

Both logistic and ordered logistic regression results support the key role of living with cats, engaging in coprophagy behaviours, and maintaining an outdoor lifestyle in increasing the risk of T. gondii infection in dogs. These identified risk factors collectively suggest that both ingesting oocysts, as observed through cat cohabitation and coprophagy, and engaging in predatory behaviours, as possible for outdoor living dogs, are indicating likely sources of T. gondii infection in this host species.

One Health Approach in Serosurvey of Toxoplasma gondii in Former Black Slave (Quilombola) Communities in Southern Brazil and Among Their Dogs

Brazilian quilombos are rural semi-isolated remnant communities of former black slaves and their descendants who traditionally maintained themselves through archaic subsistence livestock and agriculture practices and historically lacked specific public health policies. Although such individuals and their dogs may be exposed to zoonotic pathogens such as Toxoplasma gondii, no study to date has assessed these human-animal populations together. Populations in four different Brazilian quilombos in southern Brazil were evaluated. Overall, 93/208 people (44.7%) and 63/100 dogs (63.0%) were seropositive for IgG anti-T. gondii antibodies by indirect immunofluorescent antibody test (IFAT), 4/208 (1.9%) human samples seropositive for IgM anti-T. gondii antibodies, with a human-dog seropositivity ratio for IgG of 0.71. Quilombola individuals ingesting game meat were 2.43-fold more likely (95% CI: 1.05-5.9) to be seropositive. No risk factors were associated with seropositivity among dogs, thus suggesting that their exposure to T. gondii was random. Surprisingly, our research group had previously found an inverted human-dog ratio for T. gondii seropositivity of 2.54 in the urban area of a nearby major city. Because consumption of raw/undercooked game meat by quilombola individuals may have contributed to higher exposure, higher overall seroprevalence among dogs may have also indicated interaction with wildlife. Although these dogs may hunt wildlife without their owners' awareness, the higher dog seropositivity may also be related to feeding from discarded food in the community or backyard livestock animals and drinking surface water contaminated with oocysts. Thus, wildlife cannot be singled out as the reason, and future studies should consider sampling water, soil, wildlife, and livestock tissues, to fully establish the source of infection in dogs herein.

Detection of Toxoplasma gondii oocysts in soil and risk mapping in an island environment in the Northeast of Brazil

Toxoplasmosis is an emerging and re-emerging infectious disease that can be transmitted through a contaminated environment. Environmental contamination is an emergency health issue, and determining its occurrence is fundamental to a One Health approach. In this study, we addressed the extent of environmental contamination and viability of Toxoplasma gondii oocysts in soil in different environments on Fernando de Noronha Island, Brazil. In addition, we performed species distribution modelling to predict the environmental suitability for coccidia persistence in the studied area. Soil samples were collected in 14 neighbourhoods of the Island and in the four main squares, creating a total of 95 soil samples (five samples per site). The samples were analyzed by the polymerase chain reaction (PCR) technique for the presence of the 18S ribosomal DNA gene of Apicomplexan protozoa, followed by genetic sequencing. We obtained 4.2% (4/95) positive soil samples with 100% similarity for T. gondii sequences. Two out of four positive sites on PCR showed viability of T. gondii oocysts through the mouse bioassay technique. As a result of the application of the species distribution modelling, environmental adequacy for the coccidia was observed throughout the Island. The results confirm the contamination of the soil in this insular environment by T. gondii oocysts and the environmental suitability by modelling application. These findings are an alert for the possibility of infection in animals and humans by contaminated soil, and for contamination of the maritime environment in addition to water resources for consumption by the local population.

Seropositivity of Anti-Toxoplasma gondii Antibodies in Owners and Their Dogs Living on Island and Mainland Seashore Areas of Southern Brazil

Although toxoplasmosis has been considered among the most neglected zoonoses worldwide, no study has focused on the frequency and associated risk factors of owners and their dogs living on an island and mainland seashore areas. Accordingly, anti-Toxoplasma gondii IgG antibodies were screened by indirect fluorescent antibody test (IFAT) in owners and dogs from three oceanic islands and two nearby mainland harbor areas, with associated risk factors for toxoplasmosis assessed by univariable and multivariable logistic regression models. Overall, anti-T. gondii seropositivity was observed in 59/328 (18.0%) owners and 66/283 (23.3%) dogs, with no statistical difference between owners (p = 0.360) and dogs (p = 0.655) from islands and mainland areas. Consumption of local water springs (p = 0.016; OR = 2.11) was an associated risk factor for T. gondii seropositivity, and owners with the habit of spring water intake were twice more likely seropositive (p = 0.014; OR = 2.14). Presence of anti-T. gondii antibodies in dogs was associated with seropositive owners (p = 0.008; OR = 2.81), household consumption of beef meat (p = 0.042; OR = 1.7) and chicken (p = 0.026; OR = 2.9). Despite being lower than the worldwide prevalence, toxoplasmosis seropositivity in owners and their dogs in southern Brazil was influenced by the positive owner, water source, and meat consumption, and not by inhabiting islands or seashore mainland areas, presence of dogs, cats, or both. In addition, drinking water quality should always be considered a critical risk factor for toxoplasmosis on islands.

Seroprevalence of Toxoplasma gondii in domestic cats in tropical region of Serra da Tiririca State Park, Niterói, Rio de Janeiro

ABSTRACT The present study aimed to determine the seroprevalence of anti-T. gondii antibodies in cats of the Serra da Tiririca State Park region using the IFAT to evaluate the sex and age variables. The cats were domiciled in the region of Serra da Tiririca State Park (PESET-RJ), Rio de Janeiro. Between 2015 and 2016, a total of 86 blood samples were collected from 35 female and 51 male semi-domiciled cats that were attended to by a spay-neuter program of UFF. Samples were evaluated for anti-T. gondii immunoglobulin G by the indirect immunofluorescence reaction (IFAT) with a cut-off point of 1:40. Of the samples analyzed, 29.07% (25/86) presented anti-T gondii antibodies. There was no significant association (P> 0.05) between the variables sex and age of the animals with serology results. The results obtained in this study suggest that T. gondii has a considerable distribution among the cats of the studied region (PESET-RJ). This is the first report of the seroprevalence of T. gondii in cats from this area. Age and gender were not considered risk factors for infection by T. gondii in this group of animals studied.

A serological survey of Toxoplasma gondii in polish pigs from organic farms, other housing systems and in pigs of different age groups

Background

The consumption of raw or undercooked meat, especially pork, and offal containing infective tissue cysts is suspected to be a significant route of infection with Toxoplasma gondii. Although the use of “animal-friendly pig production systems” ensuring direct contact with the natural environment offers ethical benefits, it limits the ability to ensure animal health; it may also increase the probability of infections by pathogens such as T. gondii, and thus their entry into the food chain. This study determines the seroprevalence of T. gondii in pigs from different housing systems and farms with different hygiene standards in Poland, as well as among pigs of different age groups from farms with high hygiene standards. In total 760 pig serum samples were examined for the presence of specific antibodies using the PrioCHECK^® Toxoplasma Ab porcine commercial ELISA test (Prionics, Switzerland).

Results

Test results with PP ≥ 20% were regarded as positive, as indicated by the manufacturer. Antibodies to T. gondii were found in 193 of 760 (25.4%) tested sera. Regarding different housing systems, antibodies were found in 117 pigs: of these, 52.6% (61/116) were from organic farms, 40.9% (47/115) from farms with low hygiene standards, 5.4% (9/167) from farms with high hygiene standards and 0% (0/40) from a farm with a high level of biosecurity. Regarding age groups, antibodies were found in 76 animals on farms with high hygiene standards: 11.1% (7/63) were pigs younger than 3 months, 0% (0/60) aged 3–4 months, 12.3% (7/57) aged 5–6 months (final fattening stage) and 43.7% (62/142) were sows aged 9 months and older.

Conclusions

Antibodies to T. gondii were most often found in pigs from organic and low-hygiene farms, as well as in pigs aged 9 months and older. Meat derived from seropositive animals can pose a potential source of infection for humans. As maternal antibodies to T. gondii can be present in the blood of piglets aged up to 3–4 months, serological examination is unjustified in piglets up to this age.

One Health approach on human seroprevalence of anti-Toxocara antibodies, Toxocara spp. eggs in dogs and sand samples between seashore mainland and island areas of southern Brazil

Toxocariasis, caused by Toxocara spp. nematodes, is among the top 5 neglected parasitic diseases worldwide; however, no comprehensive study to date has serologically compared infections in people and their dogs and environmentally contaminated soil or sand of mainland and island locations. Accordingly, this study aimed to assess the seroprevalence of anti-Toxocara antibodies in traditional human seashore populations, the presence of eggs in dogs' feces and hair, and the presence of eggs in environmental samples from islands compared to the adjacent mainland of southern Brazil. Overall, 212/328 (64.6%) people were positive for Toxocara spp. antibodies, including 125/190 (65.8%) island and 87/138 (63.0%) mainland residents. For dog samples, 12/115 (10.43%) were positive for the presence of Toxocara spp. eggs, all from dogs living in islands, and 22/104 (21.15%) dog hair samples contained eggs of Toxocara spp. Environmental contamination with Toxocara spp. eggs was observed in 50/130 (38.46%) samples from all sampled sites. No significant association was found between risk factors (age, sex, educational level, monthly income, owning dogs or cats, ingestion of treated water, and consumption of raw or uncooked meat) and Toxocara spp. seropositivity. The present study is the first concurrent report on people, their dogs, and environmental contamination of Toxocara spp. The high prevalence we observed in the seashore populations of both in island and mainland areas may be caused by exposure to contaminated sand and climatic factors favoring frequent exposure to Toxocara spp. In conclusion, seashore lifestyle and living conditions of both island and mainland areas may have predisposed higher contact with infected pets and contaminated soil, favoring the high prevalence of toxocariasis.

Cross-sectional survey for Toxoplasma gondii infection in humans in Fernando de Noronha island, Brazil

Toxoplasmosis, caused by the protozoan Toxoplasma gondii, is zoonotic disease and is one of the most important foodborne parasitic diseases globally. The prevalence in humans is highly variable, being influenced by cultural habits, socioeconomic, and environmental conditions. The objective of this study was to estimate the prevalence of T. gondii infection in humans on the archipelago of Fernando de Noronha, Pernambuco State, Brazil, and to identify the risk factors associated with this infection. The seroprevalence of immunoglobulin G anti-T. gondii antibodies was 50.4% (172/341, 95% CI: 45.2%-55.7%). Factors associated with the infection were consumption of well water or rainwater (odds ratio [OR]: 2.43, p=0.020) and consumption of game meat (OR: 1.80, p=0.026). This is the first study to provide epidemiological information of T. gondii infection among the residents of the Island of Fernando de Noronha, revealing a considerable antibody seroprevalence in this population. This study provides information for the adoption of prevention and control measures in island environments.

Toxoplasma gondii in domiciled dogs and cats in urban areas of Brazil: risk factors and spatial distribution

Toxoplasma gondii is a highly prevalent zoonotic parasite in Brazil capable of infecting mammals and birds. The increase in the urban populations of pets and the narrowing of the human-animal relationship can facilitate the transmission of important public health zoonoses, such as toxoplasmosis. This study aimed to evaluate the frequency and spatial distribution of T. gondii infection and its risk factors in domiciled dogs and cats attended at the Jorge Vaitsman Institute, Rio de Janeiro. Serum samples from 400 dogs and 272 cats were evaluated by an indirect fluorescent antibody test (IFAT) for IgG anti-T. gondii antibodies. Epidemiological questionnaires were used to interview the animals' owners to identify risk factors for infection. Of the total, 34% (136/400) of dogs and 8.1% (22/272) of cats had anti-T. gondii antibodies. Breed (OR: 2.10-95%, CI 1.27-3.46) was a risk factor for dogs, while sex (OR: 3.40-95%, CI 1.10-10.52) and homemade food consumption (OR: 8.49-95%, CI 2.48-29.05) were risk factors for cats. Offal consumption was considered a risk factor for both species evaluated (OR: 2.74-95%, CI 1.38-5.43 for dogs; OR: 7.66-95%, CI 1.24-47.29 for cats). The spatial analysis showed that T. gondii seropositive animals were widely distributed in the metropolitan region of Rio de Janeiro state, with a concentration observed mainly in the west and north zones of Rio de Janeiro city. The results emphasize the importance of adopting prophylactic measures to control T. gondii transmission in domiciled dogs and cats in Rio de Janeiro, contributing positively to public health.

Toxoplasma gondii infections in dogs: 2009-2020

Toxoplasma gondii infections are common in humans and animals worldwide. The present review summarizes worldwide information on the prevalence of clinical and subclinical infections, epidemiology, diagnosis, and genetic diversity of T. gondii in dogs (Canis familiaris) from 2009-2020. Seroprevalence estimates of T. gondii worldwide were tabulated. Reports of high seroprevalence in canine population and high congenital transmission of T. gondii in dogs in Brazil are reviewed. Most reports from China were published in Chinese, and these reports are now summarized here. Dogs have an additional importance in some countries such as China, Vietnam, and Nigeria; whereas in many cities dog meat is sold commercially for human consumption and given to felids, and transmission of T. gondii could occur if meat is not cooked properly. Dogs can ingest T. gondii-infected cat feces and these oocysts remain viable after passage through the digestive tract of the dog; T. gondii DNA was found in feces of dogs from New York City parks in USA. Most clinical canine cases of toxoplasmosis were in immunosuppressed dogs, and ulcerative dermatitis was one of the main presentations. Genetic diversity based on PCR-RFLP markers using DNA derived from 133 viable T. gondii isolates from dogs from several countries is discussed. T. gondii strains from Asia and Americas were more genetically diverse than those from Africa. This review will be of interest to biologists, parasitologists, veterinarians, and public health workers.

All about Toxoplasma gondii infections in pigs: 2009-2020

Toxoplasma gondii infections are common in humans and animals worldwide. Toxoplasma gondii infection in pigs continues to be of public health concern. Pigs are important for the economy of many countries, particularly, USA, China, and European countries. Among the many food animals, pigs are considered the most important for T. gondii transmission in USA and China because viable parasites have rarely been isolated from beef or indoor raised chickens. Besides public health issues, T. gondii causes outbreaks of clinical toxoplasmosis in pigs in China, associated with a unique genotype of T. gondii (ToxoDB genotype #9 or Chinese 1), rarely found in other countries. The safety of ready to eat pork products with respect to T. gondii infection is a matter of recent debate. Here, we review in detail seroprevalence, prevalence of viable and nonviable T. gondii, epidemiology, risk assessment, diagnosis, and curing of pork products containing T. gondii for the past decade. This review will be of interest to biologists, parasitologists, veterinarians, and public health workers.

All about toxoplasmosis in cats: the last decade

Toxoplasma gondii infections are common in humans and animals worldwide. Toxoplasmosis continues to be of public health concern. Cats (domestic and wild felids) are the most important host in the epidemiology of toxoplasmosis because they are the only species that can excrete the environmentally resistant oocysts in feces. Cats can excrete millions of oocysts and a single cat can spread infection to many hosts. The present paper summarizes information on prevalence, persistence of infection, clinical signs, and diagnosis of T. gondii infections in domestic and wild cats for the past decade. Special emphasis is paid to genetic diversity of T. gondii isolates from cats. Review of literature indicates that a unique genotype (ToxoDB genotype #9 or Chinese 1) is widely prevalent in cats in China and it has been epidemiologically linked to outbreaks of clinical toxoplasmosis in pigs and deaths in humans in China; this genotype has rarely been detected in other countries. This review will be of interest to biologists, parasitologists, veterinarians, and public health workers.

Atypical Toxoplasma gondii genotype from a sheep and a pig on Fernando de Noronha Island, Brazil, showed different mouse virulence profiles

Toxoplasma gondii is a zoonotic parasite which can infect almost all warm-blooded animals. Toxoplasma gondii isolates from Brazil have greater genetic diversity with a predominance of virulent and atypical genotypes, compared with the Northern Hemisphere. Considering that previous studies have demonstrated a high seroprevalence of T. gondii antibodies in animals from Fernando de Noronha Island, the aim of this study was to isolate, genetically characterize, and determine mouse virulence of isolates of T. gondii from livestock from this Brazilian island. Two T. gondii isolates were obtained by mouse bioassay from brain from one sheep and one pig. Genotyping was performed by PCR-RFLP using 10 genetic markers (SAG1, SAG2, SAG3, BTUB, GRA6, c22- 8, c29-2, PK1, L358, and Apico) and an atypical genotype of T. gondii (ToxoDB #146) was identified for both isolates. Genotyping of four ROP loci indicated different alleles for ROP16 and mouse virulence analysis revealed different profiles (intermediate and low virulence). This is the first report of this genotype being described in a pig and a sheep.

The global seroprevalence of Toxoplasma gondii in pigs: A systematic review and meta-analysis

Toxoplasmosis, caused by the protozoan parasite Toxoplasma gondii, is an important disease with worldwide distribution. Infection can occur from ingesting raw or undercooked infected meat, and among food animal species, pork is known to be one of the main sources of meat-borne infection. Here, we present results of the first systematic review and meta-analysis on the global T. gondii seroprevalence in pigs. PubMed/MEDLINE, Scopus, and EMBASE databases were comprehensively searched for relevant studies published between January 1, 1990 and October 25, 2018. We used a random effects model to calculate pooled seroprevalence estimates with 95% confidence intervals (CI) and analyzed data from five continents. We also conducted subgroup and meta-regression analyses to evaluate the effects of geographical and climate variables on pooled seroprevalence rates. Among 1542 publications identified, 148 studies containing 150 datasets were included in the meta-analysis, and comprised 148,092 pigs from 47 countries. The pooled global T. gondii seroprevalence in pigs was estimated to be 19% (95%CI, 17-22%; 23,696/148,092), with the lowest seroprevalence in Europe (13%; 10-15%) and highest seroprevalence in Africa (25%; 17-34%) and North America (25%; 19-33%). The seropositivity rates in Asia and South America regions were (21%, 16-26%) and (23%; 17-30%), respectively. A significantly higher T. gondii seroprevalence was associated with higher mean annual temperature and lower geographical latitude. The presence of cats on farms was identified as a potential risk factor for T. gondii seropositivity (OR, 1.41; 95%CI, 1.00-2.02). Our findings highlight the importance of pigs as a possible source of human T. gondii infections.

Molecular Detection and Genetic Characterization of Toxoplasma gondii from Horses in Three Provinces of China

Horse meat and milk are an important source of nutrition for many Chinese. Previous studies have shown a fairly high prevalence of Toxoplasma gondii infection in horses. However, there is no data concerning the molecular characterization of T. gondii in horses in China. The present study tested 231 cervical lymph node samples of horses from northern China (97 from Jilin, 54 from Liaoning, and 80 from Xinjiang) for the presence of the T. gondii B1 gene by seminested PCR. The B1-positive samples were genotyped at nine nuclear loci, that is, SAG1, alternative SAG2, SAG3, BTUB, c22-8, GRA6, c29-2, PK1, and an apicoplast locus, using PCR-restriction fragment length polymorphism technique. A total of 14 (6.06%) out of 231 samples were T. gondii positive. The overall prevalence of T. gondii in the horses was 5.15% (5/97) for Jilin Province, 5.55% (3/54) for Liaoning Province, and 7.50% (6/80) for Xinjiang Uygur Autonomous Region. Of the 14 positive samples, only 2 were successfully genotyped at all loci, 5 were successfully genotyped at 5-8 loci, and all typed samples belong to ToxoDB genotype no. 9. To our knowledge, this is the first molecular characterization of the T. gondii isolates from horses in China.

Anti-Neospora caninum antibodies in feral cats on the Island of Fernando de Noronha, Brazil

Neospora caninum is a protozoan responsible for abortions, stillbirths (mainly among cattle) and neuromuscular diseases in dogs. Its importance in wild species and its impact on the environmental preservation of different ecosystems have been little described. This study aimed to investigate the presence of anti-N. caninum antibodies in feral cats on the island of Fernando de Noronha and contribute epidemiological data on this disease in these animals and its impact on the environmental preservation of the island. Serum samples from 257 feral cats on the island were analyzed through the Neospora agglutination test (NAT) to search for anti-Neospora caninum antibodies. Among the 257 serum samples analyzed, 8 (3.11%) were positive in the NAT. The antibody titers were 20 in seven animals (87.5%) and 40 in one animal (12.5%). These results demonstrate that feral cats are exposed to infection by N. caninum on the island of Fernando de Noronha, at a low frequency. Greater knowledge on this infection in this animal species in this insular environment is important for elucidating its impact on the conservation of species and the maintenance of this parasite on the island.

Spatial and simultaneous representative seroprevalence of anti-Toxoplasma gondii antibodies in owners and their domiciled dogs in a major city of southern Brazil

Toxoplasmosis, caused by Toxoplasma gondii, has traditionally been considered an important water and foodborne protozoonosis with important public health considerations. Although felids play a well-established role as definitive hosts, canine epidemiological involvement in the parasite's life cycle remains questionable and controversial. The increasing closeness of the human-dog bond, particularly seen in urban settings, has been recognized as a historically unprecedented worldwide movement. Sharing daily lives in the same households, dogs may be exposed to similar associated risks of T. gondii infection as their owners. Thus, epidemiological assessment of the intra-domiciled environment, especially among socio-economically different human populations, may provide novel information regarding the actual role of dogs in animal and human toxoplasmosis. Despite spatial approaches being recently used for other water and foodborne diseases, no study has been conducted on the simultaneous spatial seroprevalence of both human and animal IgG anti-T. gondii antibodies in urban areas of major cities. Accordingly, the aim of the present study was to assess the seroprevalence and associated variables of Toxoplasma infection in owners and their domiciled dogs in Londrina, southern Brazil. Human and canine seroprevalence rates and variables associated with seroprevalence were investigated through representative random sampling among 564 households, which included 597 owners and 729 dogs. Overall, statistically significant differences between the seroprevalence of human and dog anti-T. gondii antibodies were found by Immunofluorescence Antibody Testing in 248/597 (41.54%) owners and 119/729 (16.32%) dogs. Through multiple analysis, significant concomitant variables for seropositivity of household individuals (people and dogs) were determined, including public sewer service, yard cleaning frequency, and having a dirty yard. Although no statistically significant multiple logistic model was observed among owners, univariate analysis detected associations with monthly income, soil contact, and occupation. Among dogs, the absence of other dogs and the absence of a dirty yard were concomitant significantly protective associated factors. Age differences between seropositive and seronegative individuals was significant only for human beings, with the median age of negative individuals significantly higher than positive individuals. Although no spatial clusters were identified for humans or residences, a significant cluster was identified for dogs. In conclusion, characteristics of urban toxoplasmosis may include significantly higher owner seroprevalence than their owned dogs, with canine seroprevalence directly associated with having more dogs and a dirty backyard, and spatial differences in both human and dog exposures. Although not a good indicator for human foodborne diseases, dogs may be a reliable sentinel for environmental infection. Moreover, such a holistic approach may provide crucial information for more focused prevention and monitoring programs, particularly in households with multiple pets and trash-filled backyards.