Baylisascaris Procyonis Infections in Wildlife

Baylisascaris procyonis is a parasitic nematode endemic to raccoons (Procyon lotor) that has emerged as a significant cause of larva migrans in a wide range of vertebrate hosts. Adult worms inhabit the intestinal tract of raccoons, the definitive host, where they produce vast numbers of eggs excreted in faeces. These eggs become infective after embryonation in the environment and can persist for years due to their resistance to adverse conditions. When ingested by an intermediate or paratenic host, such as small mammals or birds, the larvae migrate through tissues, often reaching the central nervous system and causing visceral, ocular or neural larva migrans. This tissue migration can result in severe neurological damage or death. In wildlife populations, B. procyonis contributes to morbidity and mortality across diverse taxa, from rodents to large ungulates, and poses a spill-over risk to humans and domestic animals. Environmental factors, such as raccoon density, latrine distribution and habitat fragmentation, influence transmission dynamics. Increasing urbanisation and translocation of raccoons have facilitated the expansion of B. procyonis into new regions, raising concerns for conservation and public health. Surveillance efforts and management strategies, including habitat modification and targeted anthelmintic baiting, are under investigation to mitigate transmission. Understanding the ecology of B. procyonis in wildlife is essential for the design of integrated control measures and for predicting zoonotic risk in changing landscapes.

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Baylisascaris Procyonis Infections in Wildlife publication trend

The graph below shows the total number of articles in baylisascaris procyonis infections in wildlife across all publications each year (not limited to Nature Index journals).

Technical terms

Definitive host: The organism in which a parasite reaches sexual maturity and reproduces.

Intermediate host: A species that harbours the parasite in a developmental stage but not the adult form.

Larva migrans: Tissue migration by nematode larvae causing inflammatory damage in host organs.

Paratenic host: A transport host that carries infective stages without further parasite development.

Embryonation: The process by which parasite eggs develop into an infective larval stage.

References

1. First report of the zoonotic nematode Baylisascaris procyonis in non-native raccoons (Procyon lotor) from Italy. Parasites & Vectors (2022).
2. Spread of the Zoonotic Nematode Baylisascaris procyonis into a Naive Raccoon Population. EcoHealth (2023).
3. Early Release - Geographic Distribution of Raccoon Roundworm, Baylisascaris procyonis, Germany and Luxembourg - Volume 26, Number 4—April 2020 - Emerging Infectious Diseases journal - CDC. Emerging Infectious Diseases (2020).