Diseases in nature

This page is about ways diseases can affect animals living in the wild. For information about what animals’ lives are like in the wild, see our section on the situation of animals in the wild.

Think of the immense suffering that disease caused to human beings before the advent of modern medicine; this is the situation of animals in the wild. The harms diseases cause are worsened by lack of access to treatment and, sometimes, the lack of opportunity to rest and recuperate. In addition to their debilitating effects on the body’s ability to function and recover, illness and diseases can increase the negative effects of environmental conditions and other stressors faced by wild animals. The result can be increased suffering and death.1

An animal only has a finite amount of energy at any time and must make trade-offs. Animals who are dying from a disease may choose to use their energy to reproduce rather than to fight off disease. This means that animals of species that provide parental care may be unable to take care of their offspring when they are sick, and leave their children more vulnerable after they die.2

 

Sickness behaviors

Many animals have evolved to avoid showing signs of illness. Animals who look weak or vulnerable are prime targets for predators. Moreover, those who live in groups may lose social status or be abandoned and left to fend for themselves when they are least able.

Alternatively, sometimes animals selectively exhibit sickness behaviors such as lethargy and sleepiness. This happens when the sickness behaviors are not caused by the illness itself, but rather by conserving energy to fight off an illness. Depending on the time of year and other circumstances, showing signs of illness might reduce opportunities to reproduce or make it impossible to defend valuable territory. An animal might take more time to rest and recover outside of breeding season, rather than trying to defend their territory. During breeding season, they might use their energy to reproduce and defend their nests or dens rather than on recovery efforts.3

Therefore, an animal can be suffering greatly from a disease or illness that we cannot recognize without performing medical checks. As more research is undertaken on how animals are affected by diseases in the wild, our knowledge in this area continues to grow.4 In the meantime, there are recognizable behavioral signs in some animals who are experiencing fevers, including lethargy, decreased appetite, and reduced grooming, though as mentioned above, animals may be able to choose not exhibit these behaviors if the cost is too high.5 Humans can also learn a lot by observing larger animals in hospitals or by doing autopsies.

Some noninvasive technologies are sensitive enough to identify indicators of health. Infrared imaging and video, bioacoustics, and analysis of feces, fur, feathers, and shed skin can provide information about diet, movement, interactions, body temperature, resting, and migrating (or not). These methods can work in difficult terrain and harsh climates, and can be used to collect information about members of hidden and nocturnal species that are otherwise hard to observe. For example, thermal imaging is used to determine the causes of lameness, injuries, and inflammations of the locomotor system, to diagnose infectious diseases, and to assess stress levels.6

Some animals are hard to observe at all, such as small animals who spend most of their lives hiding underground and extremely numerous tiny invertebrates. Marine animals can also be difficult to study because of their numbers and because it’s more difficult to study them non-invasively. As a result of these factors and a relative lack of interest in studying the topic, there is a tendency to underestimate the amount of suffering caused by diseases in the wild. Diseases that can be transmitted to humans or domesticated animals are better known.7

There are so many diseases that affect nonhuman animals in nature that they cannot all be listed here. Some of them are illnesses humans can suffer from too, like flu, pneumonia, tuberculosis, cholera, ebola, anthrax, E. Coli, salmonella, diphtheria, and rabies. Cancer is also common in both land and marine animals.8 Some populations of whales suffer from cancer at similar rates to humans.9 Other common diseases that can infect animals living in the wild are distemper, chronic wasting disease, African swine fever, worms, and a variety of fungal infections. Parasite infestations are also common,10 and are more prevalent and severe in animals whose immune systems are weakened by other factors, such as infectious disease, weather, malnutrition, bodily changes,11 or stress due to antagonistic relationships with other animals.

 

Diseases in invertebrates

When it comes to diseases in animals, most people don’t think much about how invertebrates might suffer. They contract bacterial, viral, and fungal infections like other animals do. Some are very specific to the types of animals they infect and don’t spread to vertebrates, but they can be treated similarly, with vaccines, antibiotics, and antifungals.12 Here are some common diseases found in land-dwelling and marine invertebrates.

 

Black Death in Butterflies

One major disease that affects butterflies is Nuclear Polyhedrosis Virus, or the Black Death. It’s called this because those affected become lethargic and their bodies start to decay, turning black. Their insides then liquefy and ooze out of their decaying body. The virus usually strikes in the caterpillar phase. It causes a great deal of stress to the caterpillar, who will refuse to eat and may regurgitate food. The virus can take up to three days to kill the caterpillar.13 The infected drops of the liquefied body spread easily onto leaves and is further spread by parasites, infecting the caterpillars who eat those leaves.14

 

Cricket Paralysis Virus

A widespread disease afflicting crickets is known as Cricket Paralysis Virus. Infected crickets become malnourished, have trouble jumping, lose coordination, and then their legs become paralyzed and they fall on their backs, where they lie for a few days before dying. It is unclear if this causes any stress or suffering to the cricket. It can also infect other insects, and similar strains infect bees and flies. It is spread by oral contact with feces. The virus was first discovered in Australia, but since then, versions of it have been discovered across the world. It might not be the same strain of virus, but the effects are the same, killing up to 95% of those affected.15

 

Lobster Shell Disease

Lobsters suffer from a common disease known simply as Shell Disease. Healthy lobsters have a slippery protective layer that prevents the shell from being eroded by bacteria. With shell disease, this barrier disappears, causing the shell to erode and become melanized (change color). Lobsters living in warmer water are more susceptible. The disease itself is not always lethal, but it can cause the lobster distress and weakness that increases vulnerability to other harms such as injury and predation.16

 

White Spot Syndrome Virus in crabs, crayfish, and shrimps

Viruses are extremely common in marine environments. White spot syndrome is a lethal and highly contagious virus that affects shrimps, crayfish, and other marine arthropods. Entire populations of shrimps can be infected by just one or two shrimps contracting the virus. The main symptoms are low energy, lack of appetite, and small white spots that appear all over their body. It greatly weakens the immune system and animals usually die shortly after contracting it. It is spread through the water.17

 

Withering Abalone Syndrome

Abalones can die of starvation due to withering abalone syndrome, a wasting disease. The disease is caused by bacteria that consume the digestive tract lining of infected animals. This can destroy the digestive enzymes, preventing an abalone from being able to digest food. To survive, the abalone consumes their own body mass. This causes a loss of muscle, resulting in a “withered” appearance. In their weakened state, infected animals will starve to death or be eaten by predators. It is transmitted through water-borne feces, and abalones are more susceptible to it when water temperature rises.18

 

Diseases and infections in vertebrates

More is known about diseases that affect vertebrates. Vertebrate diseases tend to be easier to study because the animals are larger and many vertebrate diseases are known to be able to pass between a variety of vertebrates, including humans and domesticated animals. The diseases below are a sampling of common diseases in vertebrates.

 

Fibropapillomatosis in sea turtles

Fibropapillomatosis is a virus that infects sea turtles. It causes swelling of tissues, hardening of blood vessels and tumors on the eyes, head, neck, flippers, and multiple internal organs. It causes emaciation and suppresses the immune system, which makes turtles susceptible to other diseases and reduces their ability to respond to other stressors in their environment. While it can go away on its own, it is frequently fatal. It is spread by trematode parasites that act as intermediate hosts.19

 

Cholera and malaria in birds

Like mammals, birds are susceptible to flu. They are also frequently stricken with cholera and malaria, though the strains are different. Avian cholera is a common bacterial disease in birds living in both temperate and arctic climates. Many birds carry the disease, but it only becomes active when the birds are physically or emotionally stressed. It causes weight loss, mucous discharge, diarrhea, and rapid breathing. It frequently leads to pneumonia. It can attack the liver, spleen, and skin and cause arthritis due to inflammation. Avian cholera can have a very high mortality rate, especially when it first spreads through a colony. In the past 50 years, the disease has been spreading both geographically and in terms of the species it afflicts, and recurrent outbreaks are common. It is spread by direct contact and by ingestion of contaminated water or soil.20 Very cold weather or high water forcing birds in temperate regions to leave their habitats are common stressors that can bring out the disease in infected birds.21

Avian malaria, which can be fatal, is a parasitic infection in birds. In some populations, 75% – 100% of the birds are carriers but it only manifests when the concentration of parasites reaches a certain level. Juvenile birds are more susceptible than adults.22

 

Chronic wasting disease in deers, elks, and bisons

Chronic wasting disease is a highly contagious disease that attacks the nervous system and multiple organs in deers, elks, and bisons, eventually creating holes in the brain.23 It may take more than a year for symptoms to manifest. Symptoms include weight loss, dehydration, poor coordination, and losing fear of humans. It is always fatal, and currently there is no vaccine and no cure. Soil and plants contaminated with infected blood or urine can infect other animals for up to 16 years.24

 

Distemper

Distemper is a viral disease related to measles that attacks the gastrointestinal, respiratory, and nervous systems of mammals. It is commonly associated with dogs but also affects many animals in the wild including raccoons, foxes, wild cats, deers, monkeys, and seals. Infected animals can exhibit behaviors similar to those caused by rabies, including drooling, circling behavior, chewing fits, nonresponsiveness to the environment, and loss of fear of humans. It can cause fever, vomiting, convulsions, and paralysis. The virus is transmitted by airborne exposure, contact with saliva, and through the placenta from mother to child. It is usually fatal. Those who survive may have permanent neurological damage.25

 

Skin diseases in amphibians, reptiles, and fishes

Amphibians are susceptible to deadly skin diseases, such as fungal infections and ranavirus. The aquatic fungal infection chytridiomycosis has been called the “deadliest pathogen on record.” It afflicts frogs, salamanders, and other amphibians in wet climates. The fungus eats through an animal’s skin, causes metabolic changes, and finally kills the animal by triggering cardiac arrest. It spreads continually from immune amphibians to those who are vulnerable.26

Ranavirus is a skin disease that infects amphibians, reptiles, and fishes. It tends to strike young amphibians and reptiles, and is fatal to susceptible animals. It causes hemorrhaging on the skin and lesions on the surface of muscles and multiple internal organs. Swelling and fluid accumulation are common, which can cause breathing and buoyancy problems. The virus spreads quickly and it can be harbored for years by resistant individuals who spread it. A susceptible population can catch it by proximity to a more resistant species. It can be transmitted through direct contact, soil and water. It can be spread between fishes and frogs and possibly spread between reptiles, amphibians, and fishes.27

 

Toxic algal blooms affecting fishes, mammals, and birds

Fishes, sea mammals, birds, and bats are often affected by toxic chemicals produced by harmful algal blooms. Land animals can be affected too. The toxins damage the animals’ central nervous systems and can seriously injure or kill them.28 It is spread by swimming in or drinking contaminated water, eating toxic algae, and breathing in airborne molecules.29

Other algal blooms don’t produce toxins but consume oxygen in the water as they decay, which affects the respiration of fishes and invertebrates. The decaying algae can also get stuck in the gills of fishes and suffocate them.30

 

Resources

The following resources list some examples which give a better sense of the scale of the suffering caused by disease among wild animals:

Animal disease information – The Center for Food Security & Public Health

A-Z list of significant animal pests and diseases – Queensland Government

Animal disease information – United States Department of Agriculture

Animal diseases – World Organisation for Animal Health

Epizone – Infectious diseases in wild and domesticated animals

Journal of Wildlife Diseases – Quarterly journal of the Wildlife Disease Association

Parasites and Diseases – Alaska government31

Diseases in nature are common, and are exacerbated by weather conditions, stresses from parasite infestation, poor nutrition, or fear. Animals also make trade-offs in how they spend their energy. In cases where they only have enough energy for either healing from disease or reproducing, reproduction is often favored. Animals living in the wild often die from diseases that could be prevented or treated. For information on how they are already being helped in these ways, see our page Vaccinating and healing sick animals.


Further readings

Bengis, R. G.; Kock, R. A. & Fischer, J. (2002) “Infectious animal diseases: The wildlife/livestock interface”, Revue Scientifique et Technique, 21, pp. 53-65 [accessed on 28 November 2016].

Bosch, J.; Sanchez-Tomé, E.; Fernández-Loras, A.; Oliver, J. A.; Fisher, M. C. & Garner, T. W. J. (2015) “Successful elimination of a lethal wildlife infectious disease in nature”, Biology Letters, 11 (11) [accessed on 27 November 2016].

Curtis, C. F.; Brookes, G. D.; Grover, K. K.; Krishnamurthy, B. S.; Laven, H.; Rajagopalan, P. K.; Sharma, L. S.; Sharma, V. P.; Singh, D.; Singh, K. R. P.; Yasuno, M.; Ansari, M. A.; Adak, T.; Agarwal, H. V.; Batra, C. P.; Chandrahas, R. K.; Malhotra, P. R.; Menon, P. K. B.; Das, S.; Razdan, R. K.; & Vaidanyanathan, V. (1982) “A field trial on genetic control of Culex p. Fatigans by release of the integrated strain IS-31B”, Entomologia Experimentalis et Applicata, 31, pp. 181-190.

Dame, D. A.; Woodward, D. B.; Ford, H. R. & Weidhaas, D. E. (1964) “Field behavior of sexually sterile Anopheles quadrimaculatus males”, Mosquito News, 24, pp. 6-16.

Daszak, P.; Cunningham, A. A. & Hyatt, A. D. (2000) “Emerging infectious diseases of wildlife – threats to biodiversity and human health”, Science, 287, pp. 443-449.

Delahay, R. J.; Smith, G. C. & Hutchings, M. R. (2009) Management of disease in wild mammals, Dordrecht: Springer.

Dobson, A. & Foufopoulos, J. (2001) “Emerging infectious pathogens of wildlife”, Philosophical Transactions of the Royal Society of London B: Biological Sciences, 356, pp. 1001-1012.

Gortázar, C.; Delahay, R. J.; Mcdonald, R. A.; Boadella, M.; Wilson, G. J., Gavier-Widen, D. & Acevedo, P. (2012) “The status of tuberculosis in European wild mammals”, Mammal Review, 42, pp. 193-206.

Gortázar, C.; Díez-Delgado, I.; Barasona, J. A.; Vicente, J.; de la Fuente, J. & Boadella, M. (2015) “The wild side of disease control at the wildlife-livestock-human interface: A review”, Frontiers in Veterinary Science, 1, A. 27, pp. 1-27.

Han, B. A.; Park, A. W.; Jolles, A. E. & Altizer, S. (2015) “Infectious disease transmission and behavioural allometry in wild mammals”, Journal of Animal Ecology, 84 (3), pp. 637-646.

Harris, R. N. (1989) “Nonlethal injury to organisms as a mechanism of population regulation”, The American Naturalist, 134, pp. 835-847.

Hawley, D. M. & Altizer, S. M. (2011) “Disease ecology meets ecological immunology: Understanding the links between organismal immunity and infection dynamics in natural populations”, Functional Ecology, 25, pp. 48-60 [referencia: 5 de noviembre de 2016].

Holmes, J. C. (1995) “Population regulation: a dynamic complex of interactions”, Wildlife Research, 22, pp. 11-19.

Hudson, P. J. & Grenfell, B. T. (2002) (eds.) The ecology of wildlife diseases, Oxford: Oxford University Press, pp. 1-5.

Knipling, E. F. (1979) The basic principles of insect population and suppression and management. USDA handbook, Washington, D. C.: U.S. Department of Agriculture.

Newton, I. (1998) Population limitations in birds, San Diego: Academic Press.

Ng, Y.-K. (1995) “Towards welfare biology: Evolutionary economics of animal consciousness and suffering”, Biology and Philosophy, 10, pp. 255-285.

O’Dea, M. A.; Jackson, B.; Jackson, C.; Xavier, P. & Warren, K. (2016) “Discovery and partial genomic characterisation of a novel nidovirus associated with respiratory disease in wild shingleback lizards (Tiliqua rugosa)”, PLOS ONE, 11 (11) [referencia: 28 de noviembre de 2016].

Roser, M.; Ochmann, S.; Behrens, H.; Ritchie, H. (2018 [2014]) “Eradication of Diseases”, ourworldindata.org, October [accessed on 2 December 2019].

Tompkins, D. M.; Dunn, A. M.; Smith, M. J. & Telfer, S. (2011) “Wildlife diseases: From individuals to ecosystems”, Journal of Animal Ecology, 80, pp. 19-38.

Wildlife Data Integration Network (2013) “Wildlife disease: Index”, wdin.org [accessed on 23 March 2013].

Williams, E. S. & Barker, I. K. (eds.) (2008) Infectious diseases of wild mammals, New York: John Wiley and Sons.

Wobeser, G. A. (2005) Essentials of disease in wild animals, New York: John Wiley and Sons.

Wobeser, G. A. (2012) Diseases of wild waterfowl, Dordrecht: Springer.

Wobeser, G. A. (2013) Investigation and management of disease in wild animals, Dordrecht: Springer.


Notes

1 Beldomenico, P. M.; Telfer, S.; Gebert, S.; Lukomski, L.; Bennett, M. & Begon, M. (2008) “Poor condition and infection: A vicious circle in natural populations”, Proceedings of the Royal Society of London B: Biological Sciences, 275, pp. 1753-1759 [accessed on 8 April 2018].

2 Brannelly, L.A,; Webb, R.; Skerratt, L.F., Berger, L. (2016) “Amphibians with infectious disease increase their reproductive effort: evidence for the terminal investment hypothesis”, Open Biology, 6 (6) [accessed on 12 November 2019].

3 Lopes, P. C (2014) “When is it socially acceptable to feel sick?”, Proceedings of the Royal Society of London B: Biological Sciences, 281 [accessed on 14 August 2019].

4 Barlow, N. D. (1995) “Critical evaluation of wildlife disease models”, in Grenfell, B. T. & Dobson, A. P. (eds.) Ecology of infectious diseases in natural populations, Cambridge: Cambridge University Press, pp. 230-259. Branscum, A. J.; Gardner, I. A. & Johnson, W. O. (2004) “Bayesian modeling of animal- and herd-level prevalences”, Preventive Veterinary Medicine, 66, pp. 101-112. Nusser, S. M.; Clark, W. R.; Otis, D. L. & Huang, L. (2008) “Sampling considerations for disease surveillance in wildlife populations”, Journal of Wildlife Management, 72, pp. 52-60. Mcclintock, B. T.; Nichols, J. D.; Bailey, L. L.; MacKenzie, D. I.; Kendall, W. & Franklin, A. B. (2010) “Seeking a second opinion: Uncertainty in disease ecology”, Ecology Letters, 13, pp. 659-674. Camacho, M.; Hernández, J. M.; Lima-Barbero, J. F. & Höfle, U. (2016) “Use of wildlife rehabilitation centres in pathogen surveillance: A case study in white storks (Ciconia ciconia)”, Preventive Veterinary Medicine, 130, pp. 106-111.

5 Hart, Benjamin L. (1988) “Biological basis of behavior of sick animals”, Neuroscience & Biobehavioral Reviews, 12, 2, pp. 123-137.

6 Dunbar M.R.; MacCarthy, K.A. (2006) “Use of infrared thermography to detect signs of rabies infection in raccoons (Procyon lotor)”, Journal of Zoo and Wildlife Medicine, 37, pp. 518-523.

7 Simpson, V. R. (2002) “Wild animals as reservoirs of infectious diseases in the UK”, The Veterinary Journal, 163, pp. 128-146. Gortázar, C.; Ferroglio, E.; Höfle, U.; Frölich, K.; Vicente, J. (2007) “Diseases shared between wildlife and livestock: A European perspective”, European Journal of Wild Research, 53, pp. 241-256. Martin, C.; Pastoret, P. P.; Brochier, B.; Humblet, M. F. & Saegerman, C. (2011) “A survey of the transmission of infectious diseases/infections between wild and domestic ungulates in Europe”, Veterinary Research, 42 [accessed on 14 September 2019]. Washington State Department of Health (2019) “Animal transmitted diseases”, doh.wa.gov [accessed on 26 June 2019].

8 Albuquerque, T. A. F.; Drummond do Val, L.; Doherty, A.; de Magalhães, J. P. (2018) “From humans to hydra: Patterns of cancer across the tree of life”, Biological Reviews, 93, pp. 1715-1734 [accessed on 14 August 2019].

9 Martineau, D.; Lemberger, K.; Dallaire, A.; Labelle, L.; Lipscomb, T. P.; Pascal, M. & Mikaelian, I. (2002) “Cancer in wildlife, a case study: Beluga from the St. Lawrence estuary, Québec, Canada”, Environmental Health Perspectives, 110, pp. 285-292 [accessed on14 August 2019].

10 Cole, R. A. & Friend, M. (1999) “Field manual of wildlife diseases: Parasites and parisitic diseases”, Other Publications in Zoonotics and Wildlife Disease, 15 [accessed on 16 April 2014]. Dantas-Torres, F.; Chomel, B. B. & Otranto, D. (2012) “Ticks and tick-borne diseases: A One Health perspective”, Trends in Parasitology, 28, pp. 437-446.

11 Lochmiller, R. L. & Deerenberg, C. (2000) “Trade‐offs in evolutionary immunology: Just what is the cost of immunity?”, Research Center for Ornithology of the Max‐Planck‐Society, 88, pp. 87-98.

12 Raukko, E. (2018) “The first-ever in­sect vac­cine Prime­BEE helps bees stay healthy”, helsinki.fi, 31.10.2018 October [accessed on 18 august 2019].

13 Hadley, D. (2019) “Why are monarch caterpillars turning black?”, ThougtCo, July 12 [accessed on 14 August 2019].

14 Stairs, G.R. (1966) “Transmission of virus in tent caterpillar populations”, Entomological Society of Canada, 98, pp. 1100-1104.

15 Liu, K.; Li, Y.; Jousset, F.-X.; Zadori, Z.; Szelei, J.; Yu, Q.; Pham, H. T.; Lépine, F.; Bergoin, M. & Tijssen, P. (2011) “The Acheta domesticus densovirus, isolated from the European house cricket, has evolved an expression strategy unique among parvoviruses”, Journal of Virology, 85, pp. 10069-10078 [accessed on 21 August 2019]. Szeleia, J.; Woodring, J:; Goettel, M. S.; Duke, G.; Jousset, F.-X.; Liu, K. Y.; Zadori, Z.; Li, Y.; Styer, E.; Boucias, D. G.; Kleespies, R. G.; Bergoin, M. & Tijssen, P. (2011) “European crickets to Acheta domesticusdensovirus (AdDNV) and associated epizootics”, Journal of Invertebrate Pathology, 106, pp. 394-399 [accessed on 21 August 2019].

16 Groner, M. L.; Shields, J. D.; Landers, D. F.; Swenarton, J. & Hoenig, J. M. (2018) “Rising temperatures, molting phenology, and epizootic shell disease in the American lobster”, The American Naturalist, 192, pp. E163-E177 [accessed on 21 August 2019].

17 Sánchez-Paz, A. (2010) “White spot syndrome virus: An overview on an emergent concern”, Veterinary Research, 41 (6) [accessed on 21 August 2019].

18 Ben-Horin, T.; Lenihan, H. S.; Lafferty, K. D. (2013) “Variable intertidal temperature explains why disease endangers black abalone”, Ecology, 94, pp. 161-168. Friedman, C. S.; Biggs, W; Shields, J. D. & Hedrick, R (2002) “Transmission of withering syndrome in black abalone, Haliotis cracherodii leach”, Journal of Shellfish Research, 21, pp. 817-824 [accessed on 21 August 2019].

19 Aguirre, A. A.; Spraker, T. R.; Balazs, G. H. & Zimmerman, B. (1998) “Spirorchidiasis and fibropapillomatosis in green turtles from the Hawaiian islands”, Journal of Wildlife Diseases, 34, pp. 91-98 [accessed on 21 Augist 2019].

20 Iverson, S. A; Gilchrest, H. G.; Soos, C.; Buttler, I. I.; Harms, N. J.; Forbes, M. R. (2016) “Injecting epidemiology into population viability analysis: avian cholera transmission dynamics at an arctic seabird colony”, Journal of Animal Ecology, 85, pp. 1481-1490 [accessed on 19 August 2019]. Sander, J. E. “Fowl cholera”, Merck Manual: Veterinary Manual [accessed on 8 December 2019].

21 Jenkins, M. (2017) “Why did nearly 4,000 birds die in the Yolo Bypass last week?”, CBS Sacramento, 27 January [accessed on 21 August 2019].

22 Dadam, D.; Robinson, R. A.; Clements, A.; Peach, W. J.; Bennett, M.; Rowcliffe, J. M. & Cunningham, A. A. (2019) “Avian malaria-mediated population decline of a widespread iconic bird species”, Royal Society Open Science, 6 (7), pp. 182-197 [accessed on 19 August 2019].

23 Salman, M. D. (2003) “Chronic wasting disease in deer and elk: Scientific facts and findings”, Journal of Veterinary Medical Science, 65, pp. 761-768.

24 Cordova, M. G. (2019) “Expert testifies on deadly deer disease to House committee”, Cornell Chronicle, July 1 [accessed on 14 August 2019].

25 Kameo, Y.; Nagao, Y.; Nishio, Y.; Shimoda, H.; Nakano, H.; Suzuki, K.; Une, Y.; Sato, H.; Shimojima, M. & Maeda, K. (2012) “Epizootic canine distemper virus infection among wild mammals”, Veterinary Microbiology, 154, pp. 222-229. Williams, E. S. & Barker, I. K. (eds.) (2008 [2001]) Infectious diseases of wild mammals, 3rd ed., New York: John Wiley and Sons, part 1.

26 Schelle, B. C.; Pasmans, F.; Skerratt, L. F.; Berger, L.; Martel, A.; Beukema, W.; Acevedo, A. A.; Burrowes, P. A.; Carvalho, T.; Catenazzi, A.; De la Riva, I.; Fisher, M. C.; Flechas, S. V.; Foster, C. N.; Frías-Álvarez, P.; Garner, T. W. J.; Gratwicke, B.; Guayasamin, J. M.; Hirschfeld, M.; Kolby, J. E.; Kosch, T. A.; La Marca, E.; Lindenmayer, D. B.; Lips, K. R.; Longo, A. V.; Maneyro, R.; McDonald, C. A.; Mendelson, J., III; Palacios-Rodriguez, P.; Parra-Olea, G.; Richards-Zawacki, C. L.; Rödel, M.-O.; Rovito, S. M.; Soto-Azat, C.; Toledo, L. F.; Voyles, J.; Weldon, C.; Whitfield, S. M.; Wilkinson, M.; Zamudio, K. R. & Canessa, S. (2019) “Amphibian fungal panzootic causes catastrophic and ongoing loss of biodiversity”, Science, 363, pp. 1459-1463.

27 American College of Veterinary Pathologists, “Ranavirus”, acvp.org [accessed on 11 October 2019]. Miaud, C.; Pozet, F.; Grand Gaudin, N. C.; Martel, A.; Pasmans, F. & Labrut, S. (2016) “Ranavirus causes mass die-offs of alpine amphibians in the southwestern alps, France”, Journal of Wildlife Diseases, 52, pp. 242-252.

28 Pybur, M. J. & Hobron, D. P. (1986) “Mass mortality of bats due to probable blue-green algal toxicity”, Journal of Wildlife Diseases, 22, pp. 449-450 [accessed on 19 August 2019]. Castle, K. T.; Flewelling, L. J.; Bryan, J., II; Kramer, A.; Lindsay, J; Nevada, C.; Stablein, W.; Wong, D. & Landsberg, J. H. (2013) “Coyote (canis latrans) and domestic dog (canis familiaris) mortality and morbidity due to a Karenia brevis red tide in the Gulf of Mexico”, Journal of Wildlife Diseases, 49, pp. 955-964. Hussain, S. (2018) “Red tide invades Florida beaches, killing and injuring marine life”, nbcmiami.com, August 2 [accessed on 20 August 2019].

29 Centers for Disease Control and Prevention (2017) “Harmful algal bloom-associated illnesses”, cdc.gov [accessed on 21 August 2019].

30 National Oceanic and Atmoshperic Administration (2016) “What is a harmful algal bloom?”, noaa.gov, April 27 [accessed on 21 August 2019].

31 See Spickler, A. R. (2016 [2004]) “Animal disease information”, cfsph.iastate.edu [accessed on 2 October 2019]; Queensland Government. Department of Agriculture and Fisheries (2017 [2010]) “A-Z list of significant animal pests and diseases”, daf.qld.gov.au, 04 Sep [accessed on 28 October 2019]; United States Department of Agriculture. Animal and Plant Health Inspection Service (2018) “Animal disease information”, aphis.usda.gov, Nov 5 [accessed on 30 November 2019].

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