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

A silent threat behind bars: Serosurvey and associated risk factors for strongyloidiasis in female inmates and correctional officers

Strongyloidiasis has been a neglected parasitic infection caused by Strongyloides genus parasites. Despite assessment of S. stercoralis exposure in different vulnerable populations, seroprevalence in inmates worldwide remains to be fully established. Due to poor sanitation and lack of personal hygienic practices, incarcerated individuals have been considered prone to spread infectious illnesses. Accordingly, the present study has assessed exposure and associated risk factors for strongyloidiasis in women inmates and correctional officers at the Women's State Penitentiary of Parana, part of the third largest incarceration complex in Brazil at the time. Blood samplings were performed in 2020 and 2021from a total of 503 women inmates and 92 correctional officers. Participants voluntarily responded to an epidemiological questionnaire to assess associated risk factors to strongyloidiasis. Serological analysis was performed by ELISA for anti-S. stercoralis IgG detection. Statistical analysis was performed using R software, adopting a 5% level of significance. The data were submitted to univariate analysis by chi-square or Fisher´s Exact test for assessing the association among seropositivity and the variables. The variables with p-value < 0.2 in the univariate analysis were considered fit to be included in the logistic regression. In overall, 356/503 (70.8%; 95% CI: 66.7-74.6) inmates were seropositive for anti-S. stercoralis antibodies, with no statistically associated risk factor to seropositivity. A total of 57/92 (62.0%; 95% CI: 51.8-71.2) correctional officers were seropositive, and logistic regression revealed that individuals older than 50 years were more likely seropositive. In conclusion, the high endemicity observed herein has indicated a history of previous exposure to S. stercoralis and warned for a systematic strongyloidiasis screening for inmates, to prevent long term morbidity and disseminated infection during incarceration.

Seropositivity for Toxocara spp. in Individuals with Animal Hoarding Disorder in Southern Brazil: An Alarm for Public Health

PURPOSE

Animal hoarding has been associated with unhealthy human, animal and environmental conditions that predispose such individuals to serious life-threatening risks such as arson, malnutrition, cruelty and zoonosis. The study aimed to evaluate the presence of anti-Toxocara spp. antibodies among individuals with animal hoarding disorder in Curitiba, Brazil.

METHODS

65 residences with register of animal hoarder behavior were visited and 11 residences were included in the study, with a total of 19 individuals consenting participation. A short questionnaire was applied to gather information regarding hoarders and their dogs/cats, and serum samples were screened to detect antibodies (IgG) against antigens of Toxocara spp.

RESULTS

Overall, 14/19 individuals (73.7%) presented anti-Toxocara spp. antibodies. In 8/11 (72.7%) households at least one person was seropositive. Seropositivity was higher among women (10/13; 76.9%) than men (4/6; 66.7%). A total of 442 dogs (14-30 dogs; average = 23.3 per household) and 31 cats (1-20 cats; average = 4.8 per household) were observed. To the authors' knowledge, this was the first study to survey occurrences of toxocariasis among animal hoarders. The high population densities of dogs observed during visits, in conjunction with absence of veterinary care and unsanitary conditions, may indicate that situations of high levels of animal infection and soil contamination were present.

CONCLUSION

In summary, the seroprevalence observed in this study indicated that there was a high risk of Toxocara spp. infection among individuals with animal hoarding disorder. Provision of educational programs to reduce the risk of infection in this population is warranted.

Molecular Determination of Toxocara spp. Eggs Isolated from Public Parks and Playgrounds in Zahedan, Southeast Iran

Background

Human toxocariasis (HT) is a zoonotic disease with a global expansion. Contaminated soil with Toxocara spp. eggs is the main source of human infection, which may lead to severe complications depending on the organs invaded by migrating larvae.

Aim

This study is aimed at eliciting the prevalence of Toxocara spp. eggs in public parks in Zahedan, southeast Iran, and providing new insight into the soil contamination rate in this area using microscopic and molecular methods.

Methods

Based on five municipal districts, 240 soil samples were collected from public parks and playgrounds in Zahedan. The modified Sheather's flotation technique was employed to isolate Toxocara spp. eggs from the soil, followed by microscopic assessment and molecular evaluation of internal transcribed spacer 1 and 2 ribosomal deoxyribonucleic acid (ITS1 and 2 rDNA) using nested polymerase chain reaction (nested PCR) to identify the presence of Toxocara spp. eggs. The Sanger sequence was used to differentiate the Toxocara species. Subsequently, all the sequenced data were blasted and compared with other sequences available in the GenBank.

Results

Out of 240 soil samples collected, 7 (2.9%) samples were identified to contain Toxocara spp. eggs using Sheather's flotation and microscopic techniques. Meanwhile, 19 (7.9%) samples were positive using nested PCR. According to the Sanger sequencing analysis findings, all positive samples were contaminated with Toxocara cati.

Conclusion

As evidenced by the obtained results, only T. cati species were detected in public parks and playgrounds in Zahedan; therefore, control and prevention programs against this species should be considered in human and animal communities.

Serological and Molecular Survey of Brucella Species in Owners and Their Dogs Living on Island and Mainland Seashore Areas of Brazil

Background: Although Brucella abortus, Brucella suis, and Brucella canis may infect humans and dogs worldwide, no study to date has assessed and compared owners and their dogs between island and mainland seashore areas. Materials and Methods: Accordingly, the study herein has applied serological tests, including Microplate Agglutination Test with 2-Mercaptoethanol, immunochromatographic assay, and Rose Bengal Test, and a Brucella genus-specific PCR assay to 195 owners and their 148 dogs living on 1 mainland seashore area and three nearby oceanic islands of southern Brazil. Results: No seropositivity to B. abortus and B. suis was detected in owner or dog sera. Anti-B. canis seropositivity was observed in 3/148 (2.0%) dogs, but no owner sample was seropositive to B. canis. In addition, all blood samples from both owners and dogs were negative on Brucella genus-specific PCR assay. Conclusions: The seropositive dogs were not related and lived on the seashore mainland area of Guaraqueçaba city. The absence of seropositivity on the islands and the low seropositivity on the seashore mainland could be attributed to geographic isolation, and suggest the low impact of the disease in the region. Despite being a zoonotic disease, brucellosis by B. canis is not included in the National Program for Control and Eradication of Brucellosis, and its diagnosis and notification are not mandatory. The presence of seropositive dogs highlights the risk to human health and the importance of epidemiological surveillance actions in the region, as well as the need for the implantation of preventive measures to avoid the transmission of the pathogen.

Diversity of helminths with zoonotic potential and molecular characterization of Toxocara canis infecting domestic dogs from locations of Amazon and Atlantic Forest Brazilian biomes

The coproparasitological examination of dogs (n=278) from two Brazilian biomes (Amazon [AZ] and Atlantic Forest [AF]) by centrifugal flotation demonstrated positivity values of 54.2% (AF) and 48.5% (AZ). The most prevalent parasites in AF were hookworms (81.0% - 47/58), Toxocara sp. (17.3% - 10/58) and Trichuris vulpis (12.1% - 7/58); while in AZ they were hookworms (86.7% - 72/83), Toxocara sp. (18.1% - 15/83), Dipylidium caninum (13.3% - 11/83) and T. vulpis (10.8% - 9/83). PCR was performed using the partial mitochondrial genes cytochrome c oxidase subunit 1 (pcox1) and NADH dehydrogenase 1 (pnad1) in 25 fecal samples positive for Toxocara sp. eggs and found one sample positive for pcox1 and six positives for pnad1. The sequencing of these samples was unsuccessful due to the difficulties inherent in copro-PCR+sequencing. The sequencing of 14 samples of T. canis adult helminths retrieved 11 sequences of 414 bp for pcox1 and nine sequences of 358 bp for pnad1. The phylogenetic trees of these sequences confirmed the species T. canis. Intraspecific genetic variation was only observed for pnad1. This is the second study involving molecular analysis of T. canis in dogs from Brazil and adds new information through the use of pnad1.

Risk factors for toxocariasis during incarceration: the One Health intervention approach

Despite potential exposure to soil-transmitted helminths, especially when stray dogs and cats are present, toxocariasis in inmate populations remains to be established. Accordingly, the present study assessed the seroprevalence and associated risk factors of toxocariasis at the Women's State Penitentiary of Parana, Brazil. A total of 234/370 (63.2%; 95% CI 58.2-68.0) women inmates and 28/87 (32.2%; 95% CI 23.3-42.6) correctional officers were seropositive for anti-Toxocara spp. IgG by ELISA, with inmates 2.62-fold more likely positive (p = 0.00000026). The univariate model has identified that non-white (OR = 1.58, p = 0.047) and older than 39 years (OR = 1.28, p = 0.032) inmates were associated with mild but significant odds for seropositivity. Elementary or higher educational level was considered a protective factor for seropositivity. The presence of Toxocara spp. eggs was observed in 10/15 (66.7%) collected soil samples by centrifuge-flotation in Zinc Sulfate, and molecular analysis by PCR identified only Toxocara cati in these eggs. An intervention program was established with regular trap-neuter-release, with gradual removal for adoption (donation campaigns), treatment, and euthanasia when necessary (particularly due to advanced sporotrichosis). In addition, an educational awareness agenda was proposed, aiming to reduce soil contamination and accidental intake by the incarcerated population. A total of 40 feral cats were trapped, 20 males and 20 females, mostly adults. After trapping, 36 cats were neutered, treated, and microchipped in the Veterinary Teaching Hospital (VTH) at the Federal University of Paraná. Five trapped feral cats were euthanized, four diagnosed with advanced sporotrichosis, and one already neutered cat (not herein) with complications due to feline immunodeficiency virus (FIV). Female inmates presented higher seroprevalence for Toxocara spp. antibodies when compared to correctional officers, significantly associated with age, self-declared ethnicity (non-white), and lack of formal education. Despite the non-natural scenario of a state penitentiary, the One Health approach of Toxocara spp. has highlighted the interdisciplinary nature of the study and its relevance in understanding the complex interactions between human, animal, and environmental factors, particularly impacting female inmates. Further studies should establish the rate of inmate infection over time while deprived of liberty.

Prevalence and risk factors associated with Toxocara canis in dogs and humans in Egypt: A comparative approach

BACKGROUND

Dogs are the most popular pet animals worldwide, and their frequent and close contact with humans poses an increased risk of zoonotic parasite transmission. Toxocara canis infection is a highly pervasive and economically significant zoonotic infection transmitted by dogs worldwide, commonly in tropical and subtropical regions, particularly in developing countries.

OBJECTIVES

This study evaluates the epidemiological profile and associated risk factors of T. canis exposure among humans and T. canis infection in domestic dogs in two climatically different governorates in Egypt.

METHODS

Faecal samples from 360 domiciled dogs were examined using the flotation technique to detect T. canis eggs. In addition, 276 human serum samples were evaluated by enzyme-linked immunosorbent assay over a period of 10 months from May 2021 to February 2022 in the Alexandria and Qena Governorates, Egypt.

RESULTS

Shedding of T. canis was identified in 33.33% (120/360) of dogs and the overall seroprevalence in the human population was 20.65% (57/276). Lower Egypt, represented by the Alexandria Governorate, had higher canine infection (39.47%) and human seropositivity (29.87%) rates than those of Upper Egypt, represented by Qena Governorate (26.47% and 9.02% in dogs and humans, respectively). Statistical analysis of the sociodemographic characteristics of the participants revealed that handwashing, washing of vegetables and fruits and sex were associated with human T. canis exposure.

CONCLUSION

The prevalence rates of confirmed T. canis infection in the Egyptian dogs population and the associated human seropositivity rates reflect its importance as a public health concern and support the call to increase public awareness of this issue. The risk factors identified in this study can contribute to the development of more effective control and prevention strategies.

One health approach to toxocariasis in quilombola communities of southern Brazil

BACKGROUND

Toxocariasis has been listed among the most neglected parasitic diseases worldwide, with approximately one fifth of the global population exposed, particularly those living under poverty. In Brazil, communities of descendants of enslaved blacks (quilombola) have historically had some of the highest rates of vulnerability and poverty, characterized by lack of health assistance, poor quality of life, and nutritional insecurity.

METHODS

A cross-sectional sampling of quilombola individuals living in four communities of southern Brazil, as well as their dogs and the soil, was carried out from December 2021 to March 2022. Sociodemographic and other information such as water source, alimentary habits, and dog and cat ownership were gathered using a semi-structured questionnaire for assessing toxocariasis risk factors. Human serum samples were tested by ELISA for anti-Toxocara spp. IgG antibody detection was carried out on dog feces and hair, and soil samples were surveyed for presence of Toxocara spp. eggs.

RESULTS

Overall, 172/208 individuals (82.7%, 95% CI = 77.0-87.2) were seropositive, the highest seroprevalence rate to date in Brazil. Male gender (P = 0.029), educational level (P = 0.026), and drinking water source (P = 0.043) were associated with seropositivity by univariate analysis. Final logistic regression revealed increased odds (P = 0.017, OR = 7.6, 95% CI = 1.5-42.7) to have seropositivity in individuals > 50 years old (< 10 years old). As expected, individuals with soil contact were more likely seropositive (P = 0.038, OR = 4.4, 95% CI = 1.1-18.8). Although retrieved in only 5/96 (5.2%) dog feces, Toxocara spp. eggs were found in 18/60 (30.0%) soil samples.

CONCLUSIONS

The high vulnerability and seroprevalence observed in quilombola communities clearly demand a One Health approach for detection, monitoring, and prevention of infection by Toxocara spp. in both human and dog populations.

One health approach to toxocariasis in Brazilian indigenous populations, their dogs, and soil contamination

Introduction

Although socioeconomic vulnerability and lifestyle factors may contribute to the transmission of Toxocara spp., no study has investigated indigenous populations in Brazil using the One Health approach.

Methods

Accordingly, this study assessed anti-Toxocara spp. antibodies in Brazilian indigenous people and healthcare professionals by enzyme-linked immunosorbent assay. Presence of Toxocara spp. eggs (feces and hair) in dogs as definitive hosts and in soil samples of the indigenous communities were also recovered and molecularly investigated.

Results

Overall, 342/463 (73.9%) indigenous individuals and 46/147 (31.3%) non-indigenous healthcare professionals were seropositive for Toxocara spp. In addition, T. canis eggs were retrieved from 9/194 (4.6%) dog fecal samples and 4/204 (2.0%) dog hair samples, mainly from the Paraná State communities (3/42; 7.1%). Soil contamination was observed only in the Paraná State communities (36/90; 40.0%), with the molecular detection of T. canis. River water consumption was also associated with indigenous seropositivity (Odds ratio, 11.4).

Discussion

Indigenous individuals in Paraná State communities were 2.72-fold more likely to be seropositive than those in São Paulo State, likely due to a lack of sanitary infrastructure. In this scenario, a primarily soil-transmitted disease may also have become waterborne, with embryonated eggs probably spread to water supplies by rain. Full-time healthcare professionals in daily contact with indigenous communities were 9.2-fold more likely to be seropositive than professionals who visited sporadically, suggesting exposure to Toxocara spp. during their work and raising health concerns. In addition, the findings herein showed a significantly higher seroprevalence in indigenous people than in healthcare workers (χ2 = 85.5; p < 0.0001), likely due to overtime exposure to Toxocara spp. In conclusion, Brazilian indigenous communities are highly exposed to toxocariasis, with poor infrastructure and contact with contaminated river water as associated risk factors and a higher risk of infection in healthcare professionals working full-time in these communities.

Spatial Owner-Dog Seroprevalence of Leptospira spp. Antibodies in Oceanic Islands and Costal Mainland of Southern Brazil

Leptospirosis has been described as a disease neglected worldwide. Affecting humans and animals, the disease is often related to poor environmental conditions such as lack of sanitation and presence of synanthropic rodents. Despite being considered as a One Health issue, no study has focused on comparing owner-dog seroprevalence between islands and seashore mainland. Accordingly, the present study assessed anti-Leptospira spp. antibodies by applying microscopic agglutination test (MAT) methods to Leptospira and assessing associated risk factors via univariate and multivariate logistic regression analysis of owners and their dogs in islands and seashore mainland of southern Brazil. No anti-Leptospira spp. Seropositivity was found in 330 owner serum samples, while dogs presented an overall seroprevalence of 5.9%. All seropositive dogs reacted to serogroups of Leptospira interrogans, including 66.7% of Pyrogenes, 44.4% Canicola, 22.2% Icterohaemorrhagiae, 16.7% Australis; six reacted to more than one serogroup. No association was found among seropositivity and epidemiological variables, except that neighborhood dogs were less likely to be seropositive. Although no seropositivity was observed in owners, seropositivity in dogs had the potential to indicate such species as being sentinels for environmental exposure and potential human risk of infection.

Serosurvey of anti-Toxocara canis antibodies in people experiencing homelessness and shelter workers from São Paulo, Brazil

BACKGROUND

Despite being one of the most prevalent helminth parasitic zoonoses worldwide and particularly in socioeconomically vulnerable populations, toxocariasis remains to be fully investigated in persons experiencing homelessness. Accordingly, the present study has aimed to assess the seroprevalence and associated risk factors of Toxocara spp. exposure in persons experiencing homelessness and shelter workers from a day-shelter in São Paulo city, Brazil.

METHODS

Anti-Toxocara IgG antibodies were detected by enzyme-linked immunosorbent assay (ELISA). Univariable and multivariable logistic regression models were performed to assess the risks for toxocariasis.

RESULTS

Overall, anti-Toxocara IgG antibodies were detected in 89/194 (45.9%, 95% CI: 39.0-52.9%) persons experiencing homelessness, twice as high (OR = 2.2; 95% CI = 1.245-3.873; P = 0.0089) than the frequency of 22/79 (27.8%, 95% CI: 19.2-38.6) in shelter workers. College education was the only protective factor for Toxocara spp. exposure (OR: 0.23; P = 0.018) revealed by logistic regression.

CONCLUSIONS

Although indicating a multifactorial origin of toxocariasis, the present study has assessed a highly vulnerable population with high disease risks and premature death. Thus, the living conditions of the homeless population have influenced the high prevalence of anti-Toxocara antibodies verified here compared with domiciled shelter workers. Despite being less exposed, shelter and other outdoor workers may present an occupational risk to toxocariasis. Future studies should establish whether such environmental exposure might occur in persons experiencing homelessness in other regions worldwide.

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.

Phage ImmunoPrecipitation Sequencing (PhIP-Seq): The Promise of High Throughput Serology

Simple Summary

Determining the exposure or infection history of a person to a multitude of viruses is not an easy task. Typically, antibody tests detect antibodies against proteins (antigens) to only one or a few viruses. Here, we review an emerging technology called Phage ImmunoPrecipitation Sequencing (PhIP-Seq), that allows us to study the infection history of individuals to large numbers of viruses simultaneously. This technology uses bacteriophages to express and display viral antigens of choice, which are then bound by antigen-specific antibodies in patient samples. Antibody-bound bacteriophages are pulled down and identified through molecular techniques. This technology has been used in various infectious disease scenarios, including assessing exposure to different viruses, studying vaccine responses, and identifying viral cause of diseases. Despite inherent limitations in presenting only peptides, this technology holds great promise for future application in identifying novel pathogens, one health and pandemic preparedness.

Abstract

Phage ImmunoPrecipitation Sequencing (PhIP-Seq) is a high throughput serological technology that is revolutionizing the manner in which we track antibody profiles. In this review, we mainly focus on its application to viral infectious diseases. Through the pull-down of patient antibodies using peptide-tile-expressing T7 bacteriophages and detection using next-generation sequencing (NGS), PhIP-Seq allows the determination of antibody repertoires against peptide targets from hundreds of proteins and pathogens. It differs from conventional serological techniques in that PhIP-Seq does not require protein expression and purification. It also allows for the testing of many samples against the whole virome. PhIP-Seq has been successfully applied in many infectious disease investigations concerning seroprevalence, risk factors, time trends, etiology of disease, vaccinology, and emerging pathogens. Despite the inherent limitations of this technology, we foresee the future expansion of PhIP-Seq in both investigative studies and tracking of current, emerging, and novel viruses. Following the review of PhIP-Seq technology, its limitations, and applications, we recommend that PhIP-Seq be integrated into national surveillance programs and be used in conjunction with molecular techniques to support both One Health and pandemic preparedness efforts.