Sarcocystosis is a parasitic disease that affects a wide range of animals, including wildlife. The disease is caused by species of Sarcocystis, which are protozoan parasites that can infect the muscles of many animals. In wildlife, sarcocystosis can have significant impacts on individual animals, as well as on populations and ecosystems as a whole. This article will explore the causes, significance, and management of sarcocystosis in wildlife.
Cause
Sarcocystosis is caused by the protozoan parasite Sarcocystis, which has several species that can infect different animals. The parasites can be transmitted between animals through ingestion of contaminated food or water, or through predation. In the case of intermediate hosts, such as rodents, the parasites can infect the animal’s muscle tissue and form cysts, which are then ingested by definitive hosts, such as birds of prey, that feed on the infected intermediate hosts. In the case of carnivores, such as wild cats, the parasites can be transmitted through ingestion of infected prey or contaminated water sources.
Significance
Sarcocystosis can have significant impacts on wildlife, both in terms of individual animals and populations. Infected animals can experience muscle pain, weakness, and wasting, which can affect their ability to hunt or forage for food. In severe cases, the disease can be fatal. In addition, sarcocystosis can have population-level impacts, particularly in cases where the disease affects species that are already endangered or threatened. In these cases, the disease can further reduce population numbers, making it even more difficult for the species to recover.
Species Affected
Sarcocystosis can affect a wide range of wildlife species, including mammals, birds, and reptiles. In mammals, the disease has been documented in species such as deer, elk, moose, and wild boar, among others. In birds, sarcocystosis has been documented in species such as eagles, hawks, and owls, among others. Reptiles, such as snakes, have also been known to be affected by the disease.
Distribution
Sarcocystosis is a disease that affects both domestic and wild animals worldwide. The distribution of this disease is dependent on the host population and their geographic range.
Several species of Sarcocystis have been identified in wildlife populations worldwide. For example, S. calchasi and S. columbae have been reported in birds, while S. gigantea and S. suihominis have been found in pigs. S. neurona, which causes equine protozoal myeloencephalitis, has been found in opossums in North and South America. Other species have been found in different regions, such as S. singaporensis in Singapore and S. capracanis in India.
In some cases, the distribution of sarcocystosis may be influenced by the prevalence of intermediate hosts that are infected with the parasite. For example, the prevalence of S. neurona in opossums is higher in areas where there is a high prevalence of infected horses, which are the definitive host for the parasite. In other cases, environmental factors may also play a role in the distribution of sarcocystosis, such as the presence of suitable habitat for intermediate hosts.
Overall, sarcocystosis is a widespread disease that affects a variety of animal species across the globe. The distribution of the disease is largely dependent on the distribution and prevalence of the intermediate hosts, as well as other environmental factors that may influence transmission.
Transmission
Sarcocystosis can be transmitted between animals through ingestion of contaminated food or water, or through predation. In the case of intermediate hosts, such as rodents, the parasites can infect the animal’s muscle tissue and form cysts, which are then ingested by definitive hosts, such as birds of prey, that feed on the infected intermediate hosts. In the case of carnivores, such as wild cats, the parasites can be transmitted through ingestion of infected prey or contaminated water sources.
Clinical Signs
In infected animals, sarcocystosis can cause a range of clinical signs, including muscle pain, weakness, and wasting. Animals may also show signs of neurological impairment, such as tremors or difficulty moving. In some cases, the disease can be fatal, particularly in young or immunocompromised animals.
Diagnosis
Diagnosis of sarcocystosis in wildlife can be challenging, as clinical signs can be non-specific and may overlap with other diseases. Diagnosis is typically based on the presence of sarcocyst cysts in muscle tissue, which can be visualized using histological techniques. Molecular methods, such as PCR, can also be used to detect the presence of Sarcocystis DNA in tissue samples.
Treatment
There is currently no specific treatment available for sarcocystosis in wildlife. However, supportive care, such as fluids and antibiotics, may help alleviate some of the symptoms. In some cases, euthanasia may be the most humane option, particularly if the animal is suffering and there is no hope for recovery.
Management
Currently, there is no treatment available for sarcocystosis in wildlife. Therefore, management strategies are focused on prevention and control. The most effective way to prevent sarcocystosis is to minimize the risk of contamination by maintaining clean and hygienic living conditions for captive animals, and by preventing contact with infected wildlife. This includes preventing the consumption of infected animal tissues, such as the meat of wild game.
In cases where captive animals have been infected with sarcocystosis, veterinary care should be sought immediately. Quarantine measures may need to be implemented to prevent the spread of the disease to other animals. In addition, strict biosecurity protocols should be followed to prevent the introduction of the disease to uninfected populations.
For wild populations, management strategies are limited. However, studies have shown that certain practices can help reduce the prevalence of sarcocystosis. These include reducing the density of infected intermediate hosts, such as rodents, and decreasing the prevalence of infected definitive hosts, such as birds of prey. Additionally, habitat modification may help reduce the prevalence of intermediate hosts, such as by removing vegetation that provides cover for rodents.
Overall, effective management of sarcocystosis in wildlife requires a combination of preventative measures, early detection, and strict biosecurity protocols.
Conclusion
Sarcocystosis is a significant disease affecting wildlife populations worldwide with a wide range of species affected including pigs, snakes, and elk. The parasite responsible for this disease has a complex life cycle involving both intermediate and definitive hosts. Although sarcocystosis is not typically fatal, it can cause significant morbidity and may contribute to population declines in some species. There is currently no specific treatment for sarcocystosis in wildlife, and management efforts focus on reducing the risk of transmission and minimizing the impact of the disease on affected populations.
Sources
Dubey, J. P. (2011). Toxoplasmosis of Animals and Humans, Second Edition. CRC Press.
Munday, B. L. (1992). Sarcocystosis in free-ranging wildlife. Journal of wildlife diseases, 28(3), 369-398.
Cheadle, M. A., Yabsley, M. J., & Lindsay, D. S. (2019). Sarcocystis neurona and Related Sarcocystis Species. Veterinary Clinics of North America: Equine Practice, 35(1), 71-89.
Wünschmann, A., Sells, S., & Marsh, A. E. (2014). Sarcocystis spp. in North American birds. Journal of veterinary diagnostic investigation, 26(1), 1-9.
Further Reading
Yabsley, M. J., & Davidson, W. R. (2006). Sarcocystis spp. in North American wildlife, domestic animals, and humans. Veterinary parasitology, 140(3-4), 189-222.
Jenkins, E. J., Castrodale, L. J., De Rosemond, S. J., & Dixon, B. R. (2013). Wildlife diseases and zoonoses in Alaska: opportunities for research and collaboration. Emerging infectious diseases, 19(12), 2011.
Bell, J. A., & Kutz, S. J. (2015). Ecology and impact of the parasites of the Canada lynx. EcoHealth, 12(1), 20-31.