High overlap of zoonotic helminths between wild mammalian predators and rural dogs - an emerging One Health concern?

Hookworm infections in carnivores in Iran: a One Health concern

BACKGROUND

Dogs and cats can harbor hookworms, which may contribute to zoonotic infections. This study investigates hookworm infections in carnivores from the Caspian Sea littoral region of northern Iran, focusing on molecular and morphological identification.

METHODS

A cross-sectional study was conducted between September 2015 and October 2024, involving 172 road-killed carnivores including 78 stray dogs (Canis familiaris), 62 golden jackals (Canis aureus), and 32 stray cats (Felis catus), all collected from the northern Iranian provinces of Guilan and Mazandaran.

RESULTS

Overall, 46 (26.74%) animals tested positive for hookworms. Among these, Ancylostoma caninum was found in dogs and golden jackals, Ancylostoma tubaeforme in cats, and Uncinaria stenocephala in dogs and golden jackals. Morphological analyses confirmed key differences between A. caninum and A. tubaeforme, including size, esophageal features, and bursal structure. Molecular identification was supported by 18S, ITS1-5.8S-ITS2 rDNA, 28S, and mitochondrial cytochrome c oxidase 1 (COX1) gene sequences, demonstrating high similarity with previously identified isolates in GenBank. Phylogenetic analysis of the ITS and COX1 sequences revealed distinct clades for each species, with A. caninum and A. tubaeforme clustering together in the Ancylostoma spp. group.

CONCLUSION

These results provide important insights into hookworm diversity and highlight the zoonotic risks posed by these parasites.

Microbiological Ecological Surveillance of Zoonotic Pathogens from Hamadryas Baboons in Southwestern Saudi Arabia

This study investigates parasitic and bacterial pathogens present in Hamadryas baboons (Papio hamadryas) and humans in southwestern Saudi Arabia. Fecal samples were collected from Hamadryas baboons (n = 999) from three city peripheries and humans from city centers (n = 1998) and peripheries (n = 1998) of southwestern and eastern Saudi cities. Parasitic examinations and bacterial cultures were conducted on these samples. Key findings include the identification of various parasitic and bacterial pathogens, with notable prevalences of Staphylococcus aureus (71.37% in baboons, 71.51% in humans), Blastocystis hominis (42.24% in baboons, 17.85% in humans), Cryptosporidium spp. (40.14% in baboons, 12.6% in humans), hookworms (37.44% in baboons, 18.57% in humans), Strongyloides spp. (37.34% in baboons, 17.39% in humans), Enterobius vermicularis (36.34% in baboons, 11.18% in humans), and Campylobacter spp. (29.73% in baboons, 1.86% in humans). Additionally, the prevalences of these microorganisms in human populations coexisting with baboons in southwestern city peripheries were 75.47%, 25.22%, 23.62%, 26.33%, 22.22%, 15.11%, and 3.8%, respectively. To further characterize bacterial isolates, 16S rRNA gene sequencing was used, suggesting potential zoonotic and anthroponotic cycles. The results highlight significant pathogen prevalence among both baboons and human populations in proximity to baboon habitats, indicating a potential public health risk. However, shared environmental sources, such as contaminated water, were not thoroughly assessed and could play a role in pathogen transmission. The study's focus on 18 different parasitic and bacterial pathogens allowed for the targeting of prevalent and indicative markers of zoonotic and anthroponotic transmission. In conclusion, these baseline data are crucial for the design of advanced studies to further investigate the zoonotic and anthroponotic transmission dynamics and the environmental factors influencing pathogen prevalence.

Influence of environmental factors on the occurrence of gastrointestinal and cardiopulmonary nematodes in the red fox in the semi-arid Mediterranean areas of the Iberian Peninsula

Human-induced ecosystem fragmentation is one of the drivers causing wildlife migration from their natural habitats to urban areas, among other reasons. The red fox (Vulpes vulpes) is the most abundant wild canid in the semi-arid Mediterranean areas of the Iberian Peninsula. Water scarcity may result in areas shared by synanthropic fox populations and domestic animals becoming hotspots for parasite transmission. This study describes the gastrointestinal and cardiopulmonary nematode species affecting fox populations in these semi-arid areas and the influence of environmental variables on parasite abundance. A total of 167 foxes collected from 2015 to 2021 in the Region of Murcia (SE Spain) were analysed. Parasite abundance and spatial distribution were evaluated using environmental variables and host characteristics with a Generalised Linear Model and the Moran index. Eleven species (seven from the gastrointestinal tract and four from the cardiopulmonary tract) were described. The influence of biotic and abiotic variables was studied for Angiostrongylus vasorum, Crenosoma vulpis, Uncinaria stenocephala, Toxocara canis and Toxascaris leonina. Temperature, humidity and areas of forest or agricultural land influenced the abundance of these parasites, providing optimal conditions for free-living stages of the direct life cycle nematodes and intermediate hosts. Absolute abundance distribution maps showed defined locations for C. vulpis, T. canis and T. leonina. The results for U. stenocephala, T. canis and T. leonina were particularly important as their higher abundance levels were found close to anthropized areas, which need to be carefully evaluated to prevent transmission of these nematodes between domestic and wild canids and human health.

A walk on the wild side: A review of the epidemiology of Toxocara canis and Toxocara cati in wild hosts

Toxocara species are cosmopolitan nematode parasites of companion, domestic and wild hosts. Of the 26 known species of Toxocara, only Toxocara canis and Toxocara cati are definitively zoonotic. The significance of wild carnivores as definitive hosts of T. canis and T. cati respectively, has received far less attention compared to domestic dogs and cats. Complex environmental changes have promoted increasing contact between wildlife, domestic animals and humans that can enhance the risk of pathogen spillover. This review lists a total of 19 species of wild canid host that have been shown to act as definitive hosts for T. canis and a total of 21 species of wild felid host. In general, the number of publications focusing on felid host species is fewer in number, reflecting the general paucity of data on T. cati. The wild canids that have received the most attention in the published literature include the red fox (Vulpes vulpes), the wolf (Canis lupus), and the golden jackal (Canis aureus). The wild felid species that has received the most attention in the published literature is the Eurasian lynx (Lynx lynx). Some non-canid and non-felid hosts also act as definitive hosts of Toxocara species. Certainly, red foxes would appear to be the most significant wild species in terms of their potential to transmit Toxocara to domestic dogs and humans via environmental contamination. This can be explained by their increasing population densities, encroachment into urban areas and their dietary preferences for a wide range of potential paratenic hosts. However, a major challenge remains to assess the relative importance of wild hosts as contributors to environmental contamination with Toxocara ova. Furthermore, one major constraint to our understanding of the significance of wildlife parasitism is a lack of access to samples, particularly from rare host species.

Zoonotic parasites associated with predation by dogs and cats

One of the most common behaviors of cats that have an indoor/outdoor lifestyle is to bring hunted "gifts" to their owners, represented by small mammals, reptiles and birds. Access to the outdoors by dogs and cats may represent a problematic issue, since they may be at risk of diseases, traffic accidents and ingestion of toxins. Yet, the impact of this population of roaming dogs and cats predating wildlife is another concerning issue that receives less attention. Despite these risks, most owners still prefer to give outdoor access to their pets to allow them to express their "natural instincts," such as hunting. Therefore, with a growing population of > 470 million dogs and 373 million cats worldwide, predation not only represents a threat to wildlife, but also a door of transmission for parasitic diseases, some of them of zoonotic concern. In this review, the role played by dogs, and especially cats, in the perpetuation of the biological life cycle of zoonotic parasites through the predation of rodents, reptiles and birds is discussed. Feral and domestics dogs and cats have contributed to the population collapse or extinction of > 63 species of reptiles, mammals and birds. Although the ecological impact of predation on wild populations is well documented, the zoonotic risk of transmission of parasitic diseases has not received significant attention. The parasitic diseases associated to predation vary from protozoan agents, such as toxoplasmosis, to cestodes like sparganosis and even nematodes such as toxocariasis. Raising awareness about predation as a risk of zoonotic parasitic infections in dogs and cats will aid to create responsible ownership and proper actions for controlling feral and free-roaming cat and dog populations worldwide.

Biodiversity data supports research on human infectious diseases: Global trends, challenges, and opportunities

The unprecedented generation of large volumes of biodiversity data is consistently contributing to a wide range of disciplines, including disease ecology. Emerging infectious diseases are usually zoonoses caused by multi-host pathogens. Therefore, their understanding may require the access to biodiversity data related to the ecology and the occurrence of the species involved. Nevertheless, despite several data-mobilization initiatives, the usage of biodiversity data for research into disease dynamics has not yet been fully leveraged. To explore current contribution, trends, and to identify limitations, we characterized biodiversity data usage in scientific publications related to human health, contrasting patterns of studies citing the Global Biodiversity Information Facility (GBIF) with those obtaining data from other sources. We found that the studies mainly obtained data from scientific literature and other not aggregated or standardized sources. Most of the studies explored pathogen species and, particularly those with GBIF-mediated data, tended to explore and reuse data of multiple species (>2). Data sources varied according to the taxa and epidemiological roles of the species involved. Biodiversity data repositories were mainly used for species related to hosts, reservoirs, and vectors, and barely used as a source of pathogens data, which was usually obtained from human and animal-health related institutions. While both GBIF- and not GBIF-mediated data studies explored similar diseases and topics, they presented discipline biases and different analytical approaches. Research on emerging infectious diseases may require the access to geographical and ecological data of multiple species. The One Health challenge requires interdisciplinary collaboration and data sharing, which is facilitated by aggregated repositories and platforms. The contribution of biodiversity data to understand infectious disease dynamics should be acknowledged, strengthened, and promoted.