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.

Schistosoma and Leishmania: An Untold Story of Coinfection

A remarkable characteristic of infectious diseases classified as Neglected Tropical Diseases (NTDs) is the fact that they are mostly transmitted in tropical and subtropical regions with poor conditions of sanitation and low access to healthcare, which makes transmission areas more likely to overlap. Two of the most important NTDs, schistosomiasis and leishmaniasis, despite being caused by very different etiological agents, have their pathogenesis heavily associated with immune-mediated mechanisms, and Schistosoma spp. and Leishmania spp. have been shown to simultaneously infect humans. Still, the consequences of Schistosoma-Leishmania coinfections remain underexplored. As the inflammatory processes elicited by each one of these parasites can influence the other, several changes have been observed due to this coinfection in naturally infected humans, experimental models, and in vitro cell assays, including modifications in susceptibility to infection, pathogenesis, prognostic, and response to treatment. Herein, we review the current knowledge in Schistosoma-Leishmania coinfections in both human populations and experimental models, with special regard to how schistosomiasis affects tegumentary leishmaniasis, discuss future perspectives, and suggest a few steps to further improve our understanding in this model of parasite-host-parasite interaction.

Zoonotic helminths of dogs and risk factors associated with polyparasitism in Grenada, West Indies

Canine soil-transmitted helminths (STHs) cause important zoonoses in the tropics, with varying degrees of intensity of infection in humans and dogs. This study aimed to investigate the prevalence and associated risk factors for STHs in community dogs residing in Grenada, West Indies. In May 2021, 232 canine fecal samples were examined for zoonotic helminths by microscopy (following flotation), and genomic DNA from a subset of 211 of these samples were subjected to multiplex qPCR for the detection and specific identification of hookworms, Toxocara spp. and Strongyloides. Microscopic examination revealed that 46.5% (108/232, 95% CI 40–52.9), 9% (21/232, 95% CI 5.35–12.7) and 5.2% (12/232, 95% CI 2.3–8) of the samples contained eggs of Ancylostoma spp., Toxocara spp. and Trichuris vulpis, respectively. Multiplex qPCR revealed that, 42.2% (89/211, 95% CI 35.5–48.8) were positive for at least 1 zoonotic parasite. Of these, 40.8% (86/211, 95% CI 34.1–47.3) of samples tested positive for Ancylostoma spp., 36% (76/211, 95% CI 29.5–42.9) were positive for A. caninum, 13.3% (28/211, 95% CI 9–18.6) for A. ceylanicum, 5.7% for T. canis (12/211, 95% CI 2.97–8.81) and 1% (2/211, 95% CI 0–2.26) for Strongyloides spp. (identified as S. stercoralis and S. papillosus by conventional PCR-based Sanger sequencing). Using a multiple logistic regression model, a low body score and free-roaming behaviour were significant predictors of test-positivity for these parasitic nematodes in dogs (P < 0.05). Further studies of zoonotic STHs in humans should help elucidate the public health relevance of these parasites in Grenada.

Survey on the prevalence of intestinal parasites in domestic cats (Felis catus Linnaeus, 1758) in central Nepal

INTRODUCTION

Cats (Felis catus) are the only felines that live in close contact with humans. Since cats can act as vectors, carriers, reservoirs and definitive hosts of many gastrointestinal (GI) parasites, parasitic assessment could contribute to their survival and well-being.

AIMS

The current study aimed to assess the diversity and prevalence of GI parasites in domestic and feral cats from Ratnanagar in Chitwan in Central Nepal.

METHODS

A total of 107 fresh faecal samples of cats (90 household cats and 17 feral cats) of varied ages and sex were collected and transported to the laboratory. The copromicroscopic examination was carried out following direct wet mount, formalin-ethyl acetate sedimentation, saturated salt flotation, acid-fast staining and sporulation techniques. Furthermore, associated risk factors were evaluated to ascertain the predictor of risks for parasitic acquisition.

RESULTS

The current study revealed an overall 95.3% prevalence rate with a 100% rate in feral cats and 94.4% in household cats. Altogether, 18 (17 known and one unknown) different species of GI parasites were reported with the helminths (95.3%; 11 species) and the protozoa (55.1%; seven species). Besides age and sex, outdoor lifestyle, absence or unknown history of medication and hunting behaviour of the felines are the predictors of risk. Furthermore, mixed infection was comparatively higher than single infection in the faecal samples.

CONCLUSIONS

Cats harbour a higher prevalence and greater diversity of GI parasites, and parasitism varies with age and sex. This finding can be essential for veterinarians and public health authorities for strategic treatment and for assessing the zoonotic transmission of the parasites from these felines. Importantly, an effective medication strategy for cats and owners is recommended.

Epidemiological approach to nematode polyparasitism occurring in a sympatric wild ruminant multi-host scenario

The epidemiology behind multi-host/multi-parasite systems is particularly interesting to investigate for a better understanding of the complex dynamics naturally occurring in wildlife populations. We aimed to approach the naturally occurring polyparasitism of gastrointestinal nematodes in a sympatric wild ruminant scenario present in south-east Spain. To this end, the gastrointestinal tract of 252 wild ruminants of four different species (red deer, Cervus elaphus; mouflon, Ovis aries musimon; Iberian ibex, Capra pyrenaica and fallow deer, Dama dama) were studied in Cazorla, Segura y Las Villas Natural Park (Andalusia, Spain). Of the analysed animals, 81.52% were positive for parasite infection and a total of 29 nematode species were identified. Out of these, 25 species were detected in at least two host species and 11 parasitized all ruminant species surveyed. The multi-host interaction between these nematodes and the four host species is discussed under the perspective of host family-based differences.

Parasites, Drugs and Captivity: Blastocystis-Microbiome Associations in Captive Water Voles

(1) Background: Blastocystis is a microbial eukaryote inhabiting the gastrointestinal tract of a broad range of animals including humans. Several studies have shown that the organism is associated with specific microbial profiles and bacterial taxa that have been deemed beneficial to intestinal and overall health. Nonetheless, these studies are focused almost exclusively on humans, while there is no similar information on other animals. (2) Methods: Using a combination of conventional PCR, cloning and sequencing, we investigated presence of Blastocystis along with Giardia and Cryptosporidium in 16 captive water voles sampled twice from a wildlife park. We also characterised their bacterial gut communities. (3) Results: Overall, alpha and beta diversities between water voles with and without Blastocystis did not differ significantly. Differences were noted only on individual taxa with Treponema and Kineothrix being significantly reduced in Blastocystis positive water voles. Grouping according to antiprotozoal treatment and presence of other protists did not reveal any differences in the bacterial community composition either. (4) Conclusion: Unlike human investigations, Blastocystis does not seem to be associated with specific gut microbial profiles in water voles.

Elevated Pediatric Chagas Disease Burden Complicated by Concomitant Intestinal Parasites and Malnutrition in El Salvador

The eradication of the vector Rhodnius prolixus from Central America was heralded as a victory for controlling transmission of Trypanosoma cruzi, the parasite that causes Chagas disease. While public health officials believed this milestone achievement would effectively eliminate Chagas disease, case reports of acute vector transmission began amassing within a few years. This investigation employed a cross-sectional serosurvey of children either presenting with fever for clinical care or children living in homes with known triatomine presence in the state of Sonsonate, El Salvador. Over the 2018 calendar year, a 2.3% Chagas disease seroprevalence among children with hotspot clustering in Nahuizalco was identified. Positive serology was significantly associated with dogs in the home, older participant age, and a higher number of children in the home by multivariate regression. Concomitant intestinal parasitic infection was noted in a subset of studied children; 60% having at least one intestinal parasite and 15% having two or more concomitant infections. Concomitant parasitic infection was statistically associated with an overall higher parasitic load detected in stool by qPCR. Lastly, a four-fold higher burden of stunting was identified in the cohort compared to the national average, with four-fifths of mothers reporting severe food insecurity. This study highlights that polyparasitism is common, and a systems-based approach is warranted when treating Chagas disease seropositive children.

Association of low birth weight and polyparasitic infection during pregnancy in Lambaréné, Gabon

OBJECTIVE

To report the prevalence of polyparasitism during pregnancy in the Lambaréné region of Gabon and its association with newborn birth weight.

METHOD

Pregnant women in their third trimester were recruited in a prospective study between November 2011 and March 2015. Parasite infection status was assessed microscopically in stool, urine and blood samples. Maternal demographic and obstetrical characteristics and newborns anthropometric data were collected. Multivariable logistic regression was used to assess the association between low birth weight and polyparasitism.

RESULTS

678 of 927 pregnant women were included for analysis with mean age (SD) of 25 (6.8) years. The analysis showed that 69% (468/678) were infected with at least one parasite (Plasmodium spp., Schistosoma spp., soil-transmitted helminths, filarial infections). This comprised of 38% with monoparasitism and 31% polyparasitism. The proportion of newborn babies with a weight below 2500 g (LBW) in our study was 21% (142/678). Compared to pregnant women without infection, women with monoparasitic infection had adjusted Odds Ratio confidence interval 95% CI (aOR [95%CI]) of 1.6 [0.95-2.73], those with two parasites had aOR 95%CI of 2.63 [1.51-4.62], and those with more than two parasites had aOR of 5.08 [2.5-10.38] for delivering a newborn with low birth weight.

CONCLUSION

In Lambaréné, an endemic area for multiple parasite infections, there is a high prevalence of polyparasitism in pregnant women. Polyparasitism is associated with low birth weight. Therefore, there is an urgent need for active screening and treatment of parasite infections in pregnant women to assess the potential public health benefit of such interventions.

The burden and epidemiology of polyparasitism among rural communities in Kano State, Nigeria

BACKGROUND

Parasitic infections constitute a major public health problem worldwide, particularly among underprivileged communities in developing countries including Nigeria. The present study aimed to determine the epidemiology of polyparasitism (multiple parasitic infections) among rural communities in Kano State, North Central Nigeria.

METHODS

A total of 551 individuals were screened for the presence of intestinal, urogenital and blood parasites by using different diagnostic techniques. Demographic, socioeconomic, household and behavioural characteristics were collected using a pre-tested questionnaire.

RESULTS

Overall, 84.0% (463/551) of the participants were found to be infected with at least one parasite species, with 51.2% (282/551) of them having polyparasitism. The most prevalent parasites were Plasmodium falciparum (60.6%) followed by Blastocystis sp. (29.2%) and hookworm (15.4%). No significant association was found between malaria and helminth infections (p>0.05). Univariate and multivariate analyses showed that the presence of other family members who had intestinal polyparasitism (adjusted odds ratio [AOR]=4.12; 95% CI=2.72, 6.24), walking barefoot outside (AOR=1.70; 95% CI=1.09, 2.63) and being male (AOR=1.74; 95% CI=1.14, 2.66) were the significant risk factors of intestinal polyparasitism among the population studied.

CONCLUSION

Polyparasitism is highly prevalent among rural communities in Kano State. Therefore, effective, sustainable and integrated control measures should be identified and implemented to significantly reduce the burden and consequences of these infections in rural Nigeria.

Negative Association of Interleukin-33 Plasma Levels and Schistosomiasis Infection in a Site of Polyparasitism in Rural Cameroon

Background: This study aimed to investigate the association of plasma levels of IL-33, a mucosal alarmin known to elicit type-2 immunity, with infection and liver fibrosis profiles of school children from an endemic area for Schistosoma mansoni, malaria and hepatitis (B & C) in rural Cameroon.

Methods: A cross-sectional study enrolling schoolchildren from 5 public schools was conducted. Single schistosomiasis, malaria and hepatitis infections or co-infections were assessed by kato katz, microscopy, and rapid diagnostic tests, respectively. Hepatic fibrosis was assessed by ultrasound according to WHO Niamey guidelines and plasma levels of Interleukin 33 were determined by ELISA. All statistics were performed using R studio software.

Principal findings: We found a prevalence of 13.5% (37/275), 18.2% (50/275), and 8% (22/275), respectively for schistosomiasis, malaria and hepatitis (B or C) single infections. Only 7.6% (21/275) of co-infections were reported. Although Plasma IL-33 showed a minimal negative risk for schistosomiasis infection (AOR 0.99; 95% CI 0.97–1.01), S. mansoni infected participants had lower levels of plasma IL-33 (p = 0.003) which decreased significantly as eggs burdens increased (p = 0.01) with a negative Pearson coefficient of r = −0.22. Hepatic fibrosis occurred in 47.3% (130/275) of our study population independently from plasma levels of IL-33 (AOR 1.00; 95% CI 0.99–1.01).

Conclusion/Significance: Our data failed to show an association between plasma IL-33 levels and liver disease but convincingly report on a negative association between plasma IL-33 levels and schistosomiasis infection and egg burden in school children from a polyparasitic schistosomiasis endemic area.

Lymphocyte Populations in the Adventitial Layer of Hydatid Cysts in Cattle: Relationship With Cyst Fertility Status and Fasciola Hepatica Co-Infection

Cystic echinococcosis is a worldwide zoonosis caused by the cestode Echinococcus granulosus. Two types of hydatid cysts occur in intermediate hosts: fertile cysts that generate protoscoleces from the germinal layer of the cyst, and infertile cysts that do not produce protoscoleces and are unable to continue the life cycle of the parasite. The adventitial layer, a host-derived fibrous capsule surrounding the hydatid cyst, is suggested to play an important role in local immune regulation during infection and in fertility of the cysts. Fasciola hepatica, another important parasite of cattle, induces a characteristic Th2-like immune response that could modulate the immune response against E. granulosus. Natural co-infection of both parasites is common in cattle, but no reports describe the local immune response against E. granulosus with F. hepatica infection in the same host. This study analyzed the number and distribution of T and B cells in the adventitial layer of liver and lung cysts and the relationship with cyst fertility and F. hepatica co-infection. T lymphocytes were the predominant cell type in the adventitial layer of infertile hydatid cysts and were more numerous in infertile hydatid cysts. B lymphocyte numbers were not associated with hydatid cyst fertility. Mast cells were infrequent in the adventitial layer. The number of T and B cells was not associated with F. hepatica co-infection. The present study contributes to the understanding of local immune responses in bovine cystic echinococcosis.

Multiple Parasitic Infestation in a Nine-month-old Patient: A Case Report

We are reporting the case of a nine-month-old Pakistani female with complaint of growth retardation who presented multiple intestinal parasitic infections. Probably because of contamination with fecal matter, the initial microscopic examination of the urinary sample revealed the presence of eggs of Enterobius vermicularis, cysts of Entamoeba coli, and an organism similar to mites. Stool samples were obtained after two weeks and microscopic investigation confirmed the presence of Enterobius vermicularis eggs, cysts of Entamoeba coli, and hookworm eggs. The patient was immediately subjected to mebendazole therapy associated with trimethoprim-sulfamethoxazole, to which she responded well. Follow-up stool re-examinations performed 15 and 30 days after the treatment tested negative for all parasitic ova and cysts. This study reflects the importance of considering multiple parasitic infestations in low socio-economic populations and highlights the need of improving poor hygienic conditions to prevent such infections, in particular in children.

Protozoal coinfection in horses with equine protozoal myeloencephalitis in the eastern United States

Background

Infection by 2 or more protozoa is linked with increased severity of disease in marine mammals with protozoan encephalitis.

Hypothesis/Objectives

To assess whether horses with equine protozoal myeloencephalitis (EPM) caused by Sarcocystis neurona also have evidence of infection with Neospora hughesi or Toxoplasma gondii. We hypothesized that horses with EPM would be more likely than horses with cervical vertebral stenotic myelopathy (CVSM) to be positive for antibodies to multiple protozoan parasites.

Animals

One hundred one horses with neurologic disease: 49 with EPM and 52 with CVSM.

Methods

Case review. Archived serum and cerebrospinal fluid (CSF) from 101 horses were examined. Inclusion criteria included neurologic disease, antemortem or postmortem diagnosis of EPM or CVSM, and availability of serological results or archived samples for testing. Additional testing for antibodies was performed on serum for T. gondii, as well as serum and CSF for N. hughesi.

Results

Horses with EPM were more likely than horses with CVSM to have positive immunologic results for S. neurona on serum (95.9% versus 76.9%, P = .0058), CSF (98.0% versus 44.2%, P < .00001), and serum : CSF titer ratio (91.8% versus 0%, P < .00001). Positive results for Neospora and Toxoplasma were uncommon, with total seroprevalence rates of 12.9% and 14.9%, respectively. The proportions of EPM cases testing positive for Neospora and Toxoplasma (16% and 12%) were not different from the proportions of CVSM cases testing positive (10% and 17%, P = .31 and .47, respectively).

Conclusion

Results do not indicate an important role for protozoal coinfection in EPM in the eastern United States.

Trends in Strongyloides stercoralis Faecal Larvae Detections in the Northern Territory, Australia: 2002 to 2012

Strongyloides stercoralis is a soil-transmitted helminth (STH) endemic to tropical and subtropical areas. We reviewed the temporal detection trends in patients with S. stercoralis larvae present in faecal samples, in Northern Territory (NT) Government Health facilities, between 2002 and 2012. This was a retrospective observational study of consecutive patients with microbiologically confirmed detection of S. stercoralis in faeces. The presence of anaemia, eosinophilia, polyparasitism, and geographic and demographic data, were included in the assessment. S. stercoralis larvae were present in 389 of 22,892 faecal samples (1.7%) collected across the NT over 11 years, examined by microscopy after formol ethyl acetate concentration. 97.7% of detections were in Indigenous patients. Detections, by number, occurred in a biphasic age distribution. Detections per number of faecal samples collected, were highest in the 0–5 year age group. Anaemia was present in 44.8%, and eosinophilia in 49.9% of patients. Eosinophilia was present in 65.5% of the ≤5 age group, compared to 40.8% of >5 year age (p < 0.0001). Polyparasitism was present in 31.4% of patients. There was an overall downward trend in larvae detections from 2.64% to 0.99% detections/number of faecal samples year between 2002 and 2012, consistent with the trends observed for other local STHs. S. stercoralis remains an important NT-wide pathogen.

Lessons from a study in a rural community from southern Mexico: risk factors associated to transmission and reinfection of gastrointestinal parasites after albendazole treatment

Purpose

To determine the prevalence of gastrointestinal parasites and evaluate the effect of a single dose of treatment with albendazole in a sentinel group from a rural community in southern Mexico.

Methods

Stool samples were collected from 1456 individuals aged ≥1 year during consecutive days, and examined for helminth infection using the modified Stoll dilution method. Additionally, 104 individuals were treated with a single dose of albendazole and evaluated over 21 weeks to assess reinfection. Questionnaires were administered to obtain individual and household-level data pertaining to behavior, demography, and socioeconomic status. Risk factors for reinfection after albendazole administration were determined using multiple logistic regression analyses.

Results

The prevalence of Ascaris lumbricoides was 73.9% (95% confidence interval [CI] = 71.56%-76.14%). Albendazole was 100% effective, but eggs began to be detected by 9-12 weeks posttreatment, increasing to 100% after 21 weeks. Logistic regression analysis revealed that all individuals from this study had a probability of reinfection of 1.65× each week after treatment. The prevalence of Trichuris trichiura was 57.2% (95% CI = 54.62%-59.77%) and chemotherapy was 34.7% effective. The prevalence for other minor gastrointestinal parasites ranged from 0.2% to 29.7%.

Conclusion

This was a comprehensive study on gastrointestinal parasites in a rural community from southern Mexico and, to the best of the authors' knowledge, is the first time that the effect of albendazole has been evaluated for a period of over 21 weeks following its administration. Risk factors associated with parasite transmission were linked to poverty and lack of hygiene, such as, defecating in open places, living customs (drinking piped water and/or from a well), and absence of knowledge about transmission life cycle of the parasites. Studies of this kind should be linked to health education and improvement of access to clean water and adequate sanitation to consolidate morbidity control and enhance sustainability.

The impact of multiple infections on wild animal hosts: a review

Field parasitological studies consistently demonstrate the reality of polyparasitism in natural systems. However, only recently, studies from ecological and evolutionary fields have emphasised a broad spectrum of potential multiple infections-related impacts. The main goal of our review is to reunify the different approaches on the impacts of polyparasitism, not only from laboratory or human medical studies but also from field or theoretical studies. We put forward that ecological and epidemiological determinants to explain the level of polyparasitism, which regularly affects not only host body condition, survival or reproduction but also host metabolism, genetics or immune investment. Despite inherent limitations of all these studies, multiple infections should be considered more systematically in wildlife to better appreciate the importance of parasite diversity in wildlife, cumulative effects of parasitism on the ecology and evolution of their hosts.

The health impact of polyparasitism in humans: are we under-estimating the burden of parasitic diseases?

Parasitic infections are widespread throughout the tropics and sub-tropics, and infection with multiple parasite species is the norm rather than the exception. Despite the ubiquity of polyparasitism, its public health significance has been inadequately studied. Here we review available studies investigating the nutritional and pathological consequences of multiple infections with Plasmodium and helminth infection and, in doing so, encourage a reassessment of the disease burden caused by polyparasitism. The available evidence is conspicuously sparse but is suggestive that multiple human parasite species may have an additive and/or multiplicative impact on nutrition and organ pathology. Existing studies suffer from a number of methodological limitations and adequately designed studies are clearly necessary. Current methods of estimating the potential global morbidity due to parasitic diseases underestimate the health impact of polyparasitism, and possible reasons for this are presented. As international strategies to control multiple parasite species are rolled-out, there is a number of options to investigate the complexity of polyparasitism, and it is hoped that that the parasitological research community will grasp the opportunity to understand better the health of polyparasitism in humans.