User:IAxolotlQuestions3/Wildlife disease

Lead

Wildlife diseases spread through both direct contact between two individual animals or indirectly through the environment. Additionally, human industry has created the possibility for cross-species transmission through the wildlife trade. The recent increase in wildlife disease occurrences is cause for concern among conservationists, as many vulnerable species do not have the population to recover from devastating disease outbreaks.

Transmission

Indirect

Wildlife may come in contact with pathogens through indirect vectors such as their environment by consuming infected food and water, breathing contaminated air, or encountering virulent urine or feces from an infected organism. This type of transmission is typically associated with pathogens that are able to survive prolonged periods, with or without a host organism.

The most recognizable wildlife disease that indirectly spreads are prion disease. Prion diseases are indirectly spread due to their longevity in the environment, lasting for several months once released from a host via their excretions (urine or feces). Notable animal prion diseases include chronic wasting disease in cervids, scrapie in sheep and goats, and various types of spongiform encephalopathy including bovine (also known as mad cow disease), mink, feline, and ungulate.

Direct

Disease can be spread from organism to organism through direct contact such as exposure to infected blood, mucus, milk (in mammals), saliva, or sexual fluids such as vaginal secretions and semen.

A prominent example of direct infection is facial tumor disease in Tasmanian devils, as these marsupials will repeatedly bite other individuals in the face during the breeding season. These open wounds allow transmission via blood and saliva in the devil's orifices.

Wildlife Trade

A major driver for transmission between species recently is wildlife trade, as many organisms that do not typically encounter each other naturally are in close proximity. This can include places such as wet markets as well as the illegal trade of both live and dead animals and their body parts.

The most notable example of wildlife trade impacting both animal and human health is COVID-19, originating in a wet market in Wuhan, China. The originating species has been a topic of debate as it is unclear due to the variety of species found at the market, however pangolins and bats both have been absolved of blame despite initial claims.

Conservation

Populations on the Decline

When an epidemic strikes a population of organisms, the loss of individuals can be detrimental to already fragile or fragmented populations. Many disease epidemics have largely reduced the population of their host organisms, some even increasing the possibility of an endangered or extinct status.

Notable Epidemics Impacting Species

• Chronic wasting disease in cervids, both wild and captive
• Influenza and its variations (avian and swine) impact birds and pigs respectively
• White-nose syndrome in bats
• Chytrid fungi in amphibians
• Facial tumors in Tasmanian devils
• Fibro-papillomatosis in sea turtles
• Whirling disease in various fish such as trout and salmon

Recovery

While disease can ravage a population, many wildlife are resilient and can recuperate their population loss. Human intervention can also increase the chances of species recovering from epidemics via various prevention and treatment methods. Individuals that survive epidemics can repopulate, now with disease resistance present in the gene pool of that population. This will result in future generations of a species that are less susceptible to a specific disease.

Notable Species that Recovered From Epidemics

• Canids such as foxes and coyotes steadily recovered from mange
• Black-footed ferrets recovered from Sylvatic Plague
• Sea urchins recovered from a ciliate parasite know as Philaster apodigitformis

Prevention

Culling

While easy and quick for disease management, culling has the consequence of disrupting ecosystem function and reducing biodiversity of the population due to the loss of individuals. Activists favor humane methods of prevention such as vaccination or treatment via rehab centers, as these are non-lethal forms of management.

Surveillance and Monitoring

Programs have begun to survey wildlife populations to better understand transmission and health impacts in the affected wildlife communities. Tools such as the Geographical Information System (GIS) can be utilized in order to keep track of individual occurrences of disease in order to create an overall image of disease prevalence and spread in a given area. Major zoonotic diseases such as rabies, COVID-19, influenza, and hemorrhagic fever are monitored to ensure both human health and safety as well as mitigation of impacts on wildlife. Proactive intervention can increase the likelihood of species survival while simultaneously preventing emerging pathogens from escalating to an epidemic.