Prevalence of Endoparasites in Urban Stray Dogs from Brazil Diagnosed with Leishmania, with Potential for Human Zoonoses

Occurrence of zoonotic enteric parasites in fecal samples from dogs in shelters, parks, squares and public roads, and the dog guardians' perception of zoonoses as for the risk to public health in the city of Guarapuava, Paraná, Brazil

The aim of this study was to determine the occurrence of zoonotic enteroparasites in the feces of dogs from public shelters, squares, parks, and public roads in the city of Guarapuava, Paraná, Brazil, and to evaluate the perception of dog guardians regarding zoonoses and their risk to public health. Fecal samples were collected, coproparasitological examinations were performed to detect zoonotic enteroparasites, and polymerase chain reaction (PCR) was used to identify Giardia spp. and Cryptosporidium spp. Questionnaires were given to guardians who walked their dogs in parks, squares, and public roads, as to assess their perception of zoonoses. A total of 333 samples were collected, of these 75, 123, and 135 of them were from public shelters, squares and parks, and public roads, respectively. One or more parasites were identified in 166 (50 %) samples, of which 58/75 (77 %) were from public shelters, 50/123 (41 %) from squares and parks, and 58/135 (43 %) from public roads. The parasites detected included Ancylostoma spp., Giardia spp., Trichuris spp., Toxocara spp., and Cystoisospora spp., with Ancylostoma spp. having the highest occurrence. PCR was performed on 161 samples for convenience due to financial limitations, because only a portion of the study was funded by the municipal government, of which 15.6 % were positive for Giardia spp., and all were negative for Cryptosporidium spp. In total, 246 guardians were interviewed, of which 36 % said they did not collect their animals' feces during walks, 20 % did not use anti-helminthics on their dogs, and 23 % did not know which diseases could be transmitted by feces. Therefore, we conclude that there is a high infection rate of parasites with zoonotic potential in public places, showing the need to raise awareness among guardians about the diseases transmitted by dog feces, correct vermifugation and the importance of collecting feces in public places.

Risk factors associated with dog endoparasites infection spread in East Slovak Lowland

This study aimed to determine the prevalence of endoparasites in dog feces from public places, investigate the occurrence of endoparasites in soil, and identify potential risk factors associated with the dog endoparasites infection spread in East Slovak Lowland - the region near the EU border with Ukraine. In a one-year study, a total of 803 dog fecal samples and 148 soil samples from public places were examined for the presence of endoparasite developmental stages. In general, 43.59 % of dog excrements were positive. Six different species of intestinal parasites were detected: Toxocara canis (22.65 %), Trichuris vulpis (14.07 %), family Ancylostomatidae (10.09 %), Capillaria aerophilla (5.60 %), Ascaris spp. (1.49 %). Altogether, 52.03 % of soil samples were positive for at least one endoparasites species. The occurrence of parasitic eggs in the soil was as follows: Ascaris spp. (37.16 %), Toxocara spp. (29.05 %), Trichuris spp. (29.05 %) %), family Ancylostomatidae (2.03 %) and Toxascaris leonina (2.03 %). The occurrence of endoparasites between the towns and villages varied significantly. The distribution of endoparasites in dogs and soil was affected by the population density, the minority people living in the studied territory, the number of people living in poor hygienic conditions with limited access to drinking water and the usage of sewerage. Persisting endoparasitic contamination of the environment in East Slovak Lowland forms a reservoir with zoonotic potential representing public and environmental health problems.

Occurrence of gastrointestinal parasites in dogs from Cuiabá, Mato Grosso

Gastrointestinal parasitism by helminths and protozoa poses risks to animal and human health owing to clinical changes and transmission of potentially zoonotic agents. Thus, the present study aimed to verify the occurrence of gastrointestinal parasites in dogs from the municipality of Cuiabá, Mato Grosso, Brazil, using coproparasitological tests. From June 2021 to April 2022, faecal samples were collected from domestic dogs at the Veterinary Hospital and Animal Protection Shelters in the Cuiabá municipality. A semi-structured questionnaire was applied to the owners and those responsible for the shelters to analyse the factors associated with gastrointestinal parasitism. A total of 353 faecal samples were collected and subjected to parasitological flotation and sedimentation techniques. Data were analysed using the chi-squared test and exploratory factorial analysis. The occurrence of gastrointestinal parasitism was 22.66% and the parasites found alone or in mixed infections were Ancylostoma spp., Trichuris vulpis, Toxocara spp., Dipylidium caninum, Cystoisospora spp., Giardia duodenalis, and coccidia. It was concluded that the occurrence of gastrointestinal parasites in dogs is frequent, and the variables associated with these infections were source origin, breed, age, coexistence with other animals, and dull fur.

Synthesizing the connections between environmental disturbances and zoonotic spillover

Zoonotic spillover is a phenomenon characterized by the transfer of pathogens between different animal species. Most human emerging infectious diseases originate from non-human animals, and human-related environmental disturbances are the driving forces of the emergence of new human pathogens. Synthesizing the sequence of basic events involved in the emergence of new human pathogens is important for guiding the understanding, identification, and description of key aspects of human activities that can be changed to prevent new outbreaks, epidemics, and pandemics. This review synthesizes the connections between environmental disturbances and increased risk of spillover events based on the One Health perspective. Anthropogenic disturbances in the environment (e.g., deforestation, habitat fragmentation, biodiversity loss, wildlife exploitation) lead to changes in ecological niches, reduction of the dilution effect, increased contact between humans and other animals, changes in the incidence and load of pathogens in animal populations, and alterations in the abiotic factors of landscapes. These phenomena can increase the risk of spillover events and, potentially, facilitate new infectious disease outbreaks. Using Brazil as a study model, this review brings a discussion concerning anthropogenic activities in the Amazon region and their potential impacts on spillover risk and spread of emerging diseases in this region.

Dipylidium caninum in the twenty-first century: epidemiological studies and reported cases in companion animals and humans

Background

Dipilidiosis is a parasitic disease caused by the tapeworm Dipylidium caninum. Fleas and, less frequently, lice act as an intermediate host, and their ingestion is required for infection to occur. While the disease mainly affects domestic and wild carnivores, it is also considered a zoonotic disease, with most human cases reported in children. Dipylidium caninum is considered to be the most common tapeworm infesting companion animals, but dipilidosis in humans is rare. The aims of this review were to improve current understanding of the epidemiology of this parasitosis and its management by the medical and veterinary community.

Methods

A comprehensive review of the published literature during the last 21 years (2000–2021) on the epidemiology, clinical features, diagnosis, treatment and prevention measures of D. caninum infection and dipilidiosis in companion animals and humans was conducted.

Results

Using predefined eligibility criteria for a search of the published literature, we retrieved and screened 280 publications. Of these, 161 (141 epidemiological studies, 20 case reports [16 human cases]) were considered for inclusion in this review. This parasitosis is present worldwide; however, despite being the most frequent cestode infection in animals, it is often underdiagnosed using common coprological techniques. Its diagnosis in humans has also proved challenging, being frequently confused with pinworm infection, leading to inappropriate treatment and to the persistence of the disease over time. Prevention measures include control of ectoparasites in animals and the environment, as well as regular deworming of animals, most commonly with praziquantel.

Conclusions

The diagnosis of dipilidiosis remains challenging in both animals and humans, primarily due to the low sensitivity of the diagnostic methods currently available and a lack of knowledge of the morphological characteristics of the parasite. Although treatment with the appropriate anti-cestode compounds is well tolerated and results in resolution of the infection, indiscriminate use of these compounds may predispose to an increase in resistance. Given the worldwide distribution of this parasite, it is essential to act on several fronts, with a focus on health education for children and animal owners and the control of intermediate hosts, both in animals and in the surrounding environment.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05243-5.

Examining the paradox of urban disease ecology by linking the perspectives of Urban One Health and Ecology with Cities

The ecology of zoonotic, including vector-borne, diseases in urban social-ecological systems is influenced by complex interactions among human and environmental factors. Several characteristics contribute to the emergence and spread of infectious diseases in urban places, such as high human population densities, favorable habitat for vectors, and humans' close proximity to animals and their pathogens. On the other hand, urban living can contribute to the improvement of public health through better access to health services and creation of ecological and technological infrastructure that reduces disease burdens. Therefore, urbanization creates a disease ecology paradox through the interplay of urban health penalties and advantages for individual and community outcomes. To address this contradiction, we advocate a holistic Urban One Health perspective for managing urban systems, especially their green spaces and animal populations, in ways that more effectively control the spread of zoonotic diseases. This view should be coupled with an Ecology with Cities approach which emphasizes actionable science needed for urban planning, management and policymaking; developing disease and vector surveillance programs using citizen and community science methods; and improving education and communication actions that help diverse stakeholders understand the complexities of urban disease ecology. Such measures will enable scholars from many disciplines to collaborate with professionals, government officials, and others to tackle challenges of the urban disease paradox and create more sustainable, health-promoting environments.

Epidemiologic, Clinical and Immunological Consequences of Co-Infections during Canine Leishmaniosis

Simple Summary

Canine leishmaniosis (CanL), the most severe, visceralizing form of disease caused by Leishmania infantum transmitted by phlebotomine sand flies. CanL is frequently diagnosed in the Mediterranean basin and South America, although it is also found in other regions, including the United States (U.S.). Dogs in these regions are at risk for co-infections, prominently tick-borne diseases. Our review examines epidemiologic, clinical, and immunologic mechanisms found during the most common eight CanL co-infections reported in published literature. Co-infections alter immunologic processes and disease progression impacting CanL diagnosis, therapeutic responses, and prognosis.

Abstract

Canine leishmaniosis (CanL) is a vector-borne, parasitic disease. CanL is endemic in the Mediterranean basin and South America but also found in Northern Africa, Asia, and the U.S. Regions with both competent sand fly vectors and L. infantum parasites are also endemic for additional infectious diseases that could cause co-infections in dogs. Growing evidence indicates that co-infections can impact immunologic responses and thus the clinical course of both CanL and the comorbid disease(s). The aim for this review is to summarize epidemiologic, clinical, and immunologic factors contributing to eight primary co-infections reported with CanL: Ehrlichia spp., Anaplasma spp., Borrelia spp., Babesia spp., Trypanosoma cruzi, Toxoplasma gondii, Dirofilaria immitis, Paracoccidioides braziliensis. Co-infection causes mechanistic differences in immunity which can alter diagnostics, therapeutic management, and prognosis of dogs with CanL. More research is needed to further explore immunomodulation during CanL co-infection(s) and their clinical impact.

Canine gastrointestinal parasites as a potential source of zoonotic infections in Nigeria: A nationwide survey

Dog feces may contain zoonotic parasites that contaminate the environment and serve as a potential source of infection to animals and humans. In this study, microscopic and molecular analyses were used to estimate the prevalence and intensity of gastrointestinal (GI) parasites and assess the risk factors for infection in 948 dogs in three climatically distinct zones of Nigeria. Zoonotic helminths including Strongyloides stercoralis, Ancylostoma braziliense, A. caninum and Toxocara canis were detected either as single or multiple infections in 377 (39.8 %) of dogs examined. At multiple logistic regression analyses, association was found between GI parasite infection and deworming practices and dog management. Regarding A. braziliense, A. caninum and T. canis infections, intensity of egg shedding was statistically associated with the age of the dogs and not with their sex or breed. The majority of GI parasite-positive dogs did not receive regular deworming treatment (59 %) and roamed freely (56 %) thereby constituting public health risk. This is the first nationwide survey and analyses of risk factors of GI parasites of dogs using molecular methods as confirmation of their identity. The zoonotic potential of these parasites is exacerbated by the lack of both operational national policies to control the population of free-roaming dogs and to promote responsible dog ownership, and veterinary public health programs for dogs.

Frequency of co-seropositivities for certain pathogens and their relationship with clinical and histopathological changes and parasite load in dogs infected with Leishmania infantum

In canine leishmaniosis caused by the protozoan Leishmania infantum, little is known about how co-infections with or co-seropositivities for other pathogens can influence aggravation of this disease. Therefore, the objectives of this study were to evaluate the frequency of co-infections with or co-seropositivities for certain pathogens in dogs seropositive for L. infantum and their relationship with clinical signs, histological changes and L. infantum load. Sixty-six L. infantum-seropositive dogs were submitted to clinical examination, collection of blood and bone marrow, culling, and necropsy. Antibodies against Anaplasma spp., Borrelia burgdorferi sensu lato, Ehrlichia spp. and Toxoplasma gondii and Dirofilaria immitis antigens were investigated in serum. Samples from different tissues were submitted to histopathology and immunohistochemistry for the detection of Leishmania spp. and T. gondii. Quantitative real-time PCR was used to assess the L. infantum load in spleen samples. For detection of Coxiella burnetii, conventional PCR and nested PCR were performed using bone marrow samples. All 66 dogs tested positive for L. infantum by qPCR and/or culture. Fifty dogs (76%) were co-seropositive for at least one pathogen: T. gondii (59%), Ehrlichia spp., (41%), and Anaplasma spp. (18%). Clinical signs were observed in 15 (94%) dogs monoinfected with L. infantum and in 45 (90%) dogs co-seropositive for certain pathogens. The L. infantum load in spleen and skin did not differ significantly between monoinfected and co-seropositive dogs. The number of inflammatory cells was higher in the spleen, lung and mammary gland of co-seropositive dogs and in the mitral valve of monoinfected dogs. These results suggest that dogs infected with L. infantum and co-seropositive for certain pathogens are common in the region studied. However, co-seropositivities for certain pathogens did not aggravate clinical signs or L. infantum load, although they were associated with a more intense inflammatory reaction in some organs.

Prevalence of Toxoplasma gondii Antibodies in Stray Dogs from Various Locations in West and East Malaysia

Toxoplasmosis is caused by an obligate intracellular protozoan parasite; Toxoplasma gondii, which is one of the most important zoonotic parasite worldwide. In dogs, the sexual reproductive cycle of T. gondii is lacking, and the animals are not widely consumed as food, but they are vital in the mechanical transmission of the parasite. However, there is no present data on the exposure of stray dogs to T. gondii in Malaysia. The objective of this serological survey was to determine the prevalence of T. gondii antibodies (IgG) and associated factors in stray dogs in East and West Malaysia. Antibodies to T. gondii were determined in serum samples from 222 stray dogs from 6 different states in East and West Malaysia (Peninsular Malaysia) using an Indirect ELISA. The seroprevalence for T. gondii was 23.4% (Confidence interval: CI 17.8-29.2%). Stray dogs from Selangor and Kuala Lumpur had the highest seroprevalence (32.4%; CI 13.2-45.5%) and lowest in those from Penang and Kedah (12.5%; CI 1.3-23.5%). Gender and breed were not associated with T. gondii seropositivity. However, adult dogs were more likely to be seropositive for T. gondii (OR=2.89; CI 1.1-7.7) compared with younger dogs. These results revealed that T. gondii is prevalent in stray dogs in the studied areas in Malaysia, and indicative of the level of environmental contamination of this parasite especially in urban areas.

Prevalence of intestinal parasite infections in stray and farm dogs from Spain

Dogs play a potential role as reservoirs for zoonotic parasites, being especially problematic uncontrolled dog populations such as stray and farm dogs with access to populated areas. In order to investigate the prevalence of canine intestinal parasites in at-risk dog populations, we tested a total of 233 faecal samples shed by stray and dairy farm dogs from northern Spain. Telemann method was used to detect the presence of eggs and (oo)cysts of common dog intestinal parasites and Cryptosporidium was detected by PCR. One hundred and forty eight out of 233 samples (63.5%) were positive for at least one intestinal parasite, being Ancylostomidae (35.6%; 83/233) and Trichuris (35.2%; 82/233) the parasites most frequently identified. Cryptosporidium DNA was not detected in any of the faecal samples analysed. The overall prevalence was significantly higher in stray dogs than in farm dogs (72.5% vs 58.8%). Specifically, stray dogs had a significantly higher prevalence of Ancylostomatidae, Toxocara, Toxascaris and Taenidae. These dog populations are an important source of environmental contamination with intestinal parasite forms, which could be of significance to animal and human health.

Epidemiological aspects of Ancylostoma spp. infection in naturally infected dogs from São Paulo state, Brazil

Ancylostoma spp. are the most prevalent canine nematode parasites in Brazil. Despite their widespread parasitism in juvenile dogs, infections may occur regardless of host age. Although eosinophilia is a frequent finding in experimental infections, it is uncommon in naturally infected dogs. This study aimed to evaluate the prevalence of Ancylostoma spp. and the eosinophil blood counts (EBC) in naturally infected dogs, with or without comorbidities, admitted to the Veterinary Teaching Hospital of the São Paulo State University (UNESP), School of Veterinary Medicine and Animal Science, Botucatu campus, São Paulo state, Brazil, from 2009 to 2018. All retrospective data were gathered from veterinary medical records (VMR); diagnosis of Ancylostoma infection required the identification of eggs in fecal samples by the simple flotation test (SFT). Ancylostoma-infected animals were evaluated for other intestinal parasitic coinfections (IPC) by either the SFT or the centrifugal-flotation test. Dogs free of any gastro-intestinal parasites were prospectively included in control group (Group C). Ancylostoma-infected animals were defined: Ancylostoma spp. only intestinal parasite infection (Group A), Ancyslostoma spp. with concurrent IPC (Group B), Ancylostoma spp. only intestinal parasite infection with concurrent systemic disorders (Group D), and Ancylostoma spp. with both IPC and concurrent systemic disorders (Group E). The overall prevalence of Ancylostoma spp. was 12.1% (207/1715), that was decreased from 2014 to 2018 (9.7%) relative to the 2009-to-2013 period (13.9%). Prevalence was not significantly different between dogs <1-year-old (10.7% [51/478]) and ≥ 1 year-old (11.7% [130/1109]). IPC was observed in 45.4% (93/205) of the animals positive for Ancylostoma spp., while dogs <1 year old experienced IPC more often (58.8% [30/51]) than dogs ≥1 year old (38.5% [50/130]) (P = 0.02). Group A (n = 35) exhibited median EBC of 1.05 × 10⁹/L, and an eosinophilia ratio of 34.3% that was significantly higher (P < 0.05) than Group C (0.45 × 10⁹/L and 4.1%, respectively). Both variables did not differ in Group B (n = 20), D (n = 39) or E (n = 36) in comparison to Group C (P > 0.05). By ROC curve analysis, only Group A generated a significant area under the curve (0.72). With EBC cutoff of 0.85 × 10⁹ eosinophils/L, sensitivity and specificity were 65.7% and 70.8%, respectively. Eosinophil counts alone may be helpful in raising suspicion of an Ancylostoma spp. infection if further intestinal parasites and concurrent disorders are absent. However, local prevalence data and epidemiological findings should also be evaluated, since eosinophilia is less frequently observed with Ancylostoma spp. infections in the presence of comorbidities.

Detection of Intestinal Parasites in Stray Dogs from a Farming and Cattle Region of Northwestern Mexico

Stray dogs are one of the main reservoirs of intestinal parasitic infections and some have zoonotic potential. An epidemiological survey was carried out between September 2017 and May 2018 in Mexicali Valley, this area sacrifices around 92,470 head of cattle monthly, which represents 27% of the national slaughter and has 71,307 hectares for crops. In this period the Municipal Animal Control Center during their routine visits to the Mexicali Valley captured 103 dogs. All the dogs were evaluated using copromicroscopic techniques to detect intestinal parasites. The general frequency of parasitic infections was 28.15% (29/103), the most frequent parasite being Dipylidium caninum 16.50% (17/103), followed by Taenia spp. 6.79% (7/103), Taenia hydatigena 2.91% (3/103), Taenia serialis 0.97% (1/103), Taenia pisiformis (0.97%),Toxocara canis 3.88% (4/103), Toxascaris leonina 1.94% (2/103), and Cystoisospora spp. 1.94% (2/103). No significant statistical associations were found between parasitic infections and the studied variables (sex, age, and size) however; there was a significant statistical association with the capture area. Most of the parasites found in this survey have potential to affect the human population and animal production.

TroCCAP recommendations for the diagnosis, prevention and treatment of parasitic infections in dogs and cats in the tropics

The Tropical Council for Companion Animal Parasites Ltd. (TroCCAP) is a not-for-profit organisation whose mission is to independently inform, guide and make best-practice recommendations for the diagnosis, treatment and control of companion animal parasites in the tropics and sub-tropics, with the aim of protecting animal and human health. In line with this primary mission, TroCCAP recently developed guidelines for the diagnosis, treatment and control of feline and canine parasites in the tropics. The development of these guidelines required unique and complex considerations to be addressed, often inapplicable to developed nations. Much of the tropics encompass middle-to-low income countries in which poor standards of environmental hygiene and large populations of stray dogs and cats coexist. In these regions, a range of parasites pose a high risk to companion animals, which ultimately may place their owners at risk of acquiring parasitic zoonoses. These considerations led to the development of unique recommendations with regard, for example, to deworming and endoparasite testing intervals for the control of both global and 'region-specific' parasites in the tropics. Moreover, the 'off-' or 'extra'-label use of drugs for the treatment and control of parasitic infections is common practice in many tropical countries and many generic products lack manufacturers' information on efficacy, safety, and quality control. Recommendations and advice concerning the use of such drugs and protocols are also addressed in these guidelines. The formation of these guidelines is an important first step towards improving the education of veterinarians specifically regarding best-practice for the diagnosis, treatment and control of canine and feline parasites in the tropics.

A Leishmania infantum hypothetical protein evaluated as a recombinant protein and specific B-cell epitope for the serodiagnosis and prognosis of visceral leishmaniasis

The serodiagnosis of visceral leishmaniasis (VL) presents problems related to the sensitivity and/or specificity of the tests. In this context, more refined antigens should be identified and applied for the improvement of disease diagnosis. In the present study, DNA with an encoding of a Leishmania infantum hypothetical protein, LiHyC, was cloned, and the recombinant protein was expressed, purified, and evaluated for the serodiagnosis of canine and human VL. In addition, a specific B-cell epitope present in the LiHyC sequence was predicted; the peptide was both synthetized and evaluated in the ELISA experiments. For comparison, commercial diagnostic kits were used against positive (VL hosts) and negative (healthy hosts) samples. Results showed that the recombinant protein (rLiHyC) and synthetic peptide (PeptC) were highly sensitive and specific to diagnose canine and human VL, with 100% sensitivity and specificity, while no false-positive or false-negative result was detected. When the DPP® CVL kit was used to identify canine samples, 44 and 52 of the 60 L. infantum-infected animals, without or with clinical signals of disease, respectively, were identified, while eight and four samples were considered as false-negatives, respectively. For human VL, an IT LEISH® kit was used, and 33 of the 40 VL patients were identified, while seven samples were considered to be false-negatives. Post-therapeutic serological follow-up testing sera samples from treated and untreated VL patients showed a significant drop in the anti-PeptC and anti-rLiHyC antibody levels, thus suggesting the feasibility to use the recombinant protein and/or synthetic peptide in future studies as diagnostic and/or prognostic markers for VL.

Cannabis, One Health, and Veterinary Medicine: Cannabinoids' Role in Public Health, Food Safety, and Translational Medicine

Public health is connected to cannabis with regard to food, animal feed (feed), and pharmaceuticals. Therefore, the use of phytocannabinoids should be examined from a One Health perspective. Current knowledge on medical cannabis treatment (MCT) does not address sufficiently diseases which are of epidemiological and of zoonotic concern. The use of cannabinoids in veterinary medicine is illegal in most countries, mostly due to lack of evidence-based medicine. To answer the growing need of scientific evidence-based applicable medicine in both human and veterinary medicine, a new approach for the investigation of the therapeutic potential of cannabinoids must be adopted. A model that offers direct study of a specific disease in human and veterinary patients may facilitate development of novel therapies. Therefore, we urge the regulatory authorities-the ministries of health and agriculture (in Israel and worldwide)-to publish guidelines for veterinary use due to its importance to public health, as well as to promote One Health-related preclinical translational medicine studies for the general public health.