key: cord-023706-gs3oo3no
authors: Kaandorp, Jacques
title: Veterinary Challenges of Mixed Species Exhibits
date: 2011-06-22
journal: Fowler's Zoo and Wild Animal Medicine
DOI: 10.1016/b978-1-4377-1986-4.00004-4
sha: 
doc_id: 23706
cord_uid: gs3oo3no

nan

with acknowledgement of the original source. These permissions are granted for free by Elsevier for as long as the COVID-19 resource centre remains active.

Modern zoos like to show larger groups of animals, preferably in natural habitat-like mixed species exhibits, but it is not always easy to combine different species in one exhibit. The size of an exhibit is essential when mixing animals, especially when mixing larger mammals. Aviaries and aquaria are examples with a long-standing experience of combining various species, but in mammals this experience is often poor. Most often, zoos still show single species exhibits because of lack of space or simply to prevent problems associated with mixing different species. Safari parks in Europe were very popular in the 1960s, showing more natural displays of animals. However, because of the difficulties of handling animals in mixed exhibits, many of these parks later closed their gates. The parks that remained and still exist gained experience regarding which species may be kept together with others and which species shouldn't be mixed. The main advantage of mixed species enclosures is behavioral enrichment (Fig. 4-1 ) and the obvious educational value. There are even mixed species exhibits of carnivores. For example, Dierenrijk in Nuenen, The Netherlands, combines European grey wolves (Canis lupus) with European brown bears (Ursus arctos; Fig. 4 -2) and Gelsenkirchen Zoo, Germany, combines arctic foxes (Vulpes lagopus) with Kodiak bears (Ursus arctos middendorffi; Fig. 4-3) .

In this chapter, an incomplete listing of diseases and problems is presented to make the reader aware of the broad variety of veterinary challenges of mixed species exhibits. It is meant to encourage ideas and suggest further reading in veterinary literature about specific diseases and problems when mixing different species of animals. Veterinary problems arising because of keeping different species together may be categorized as trauma, nutrition-related problems, infectious diseases, and parasitic diseases.

In mixed species exhibits, trauma is the most frequent and serious cause of health problems ( Fig. 4-4) . 6 Competition for nesting sites in birds, establishment of territories, and competition for food and watering stations in all taxa may provoke fighting and trauma in mixed exhibits such as aviaries and large exhibits of mammals. For example, young antelopes born outside will be chased in the beginning of their lives by curious zebras, leading to death or a fatal myopathy, as has also been seen in young or newborn giraffes 1 and antelopes. Play of young animals may not be understood by other species (Fig. 4-5 ). Pinioned birds fly in unrecognizable ways in the eyes of other animals and may become victims of other birds or mammals. Another factor is that when animals are frightened because of thunder or other events, or when animals are chased by other animals because of unexpected or differing circumstances, fleeing against fences or walls may cause fatal trauma.

Seasonal aggression, especially in deer (rut), may lead to interspecies conflicts, but different males of the Artiodactylae family will fight intraspecifically over their territory or interspecifically with other animals to protect their herd (Fig. 4-6 ). Antlers and horns are weapons capable of causing stab wounds, fractures, or even immediate death. Capping horns and cutting of antlers may limit the severity of trauma. 6 After traumatic injuries, pathologic studies should always be carried out. For example, when birds kill one another, pathology often reveals underlying disease and explains the noticed aggression. 6 To prevent trauma, next to appropriate size of the exhibit, pole gates (creeps), where small animals can flee from larger animals, creation of large obstacles in phillipsi) and sable antelope (Hypotrachus niger), or toxicities such as vitamin E toxicity in pelicans or iron storage disease in birds and some primate species, should be avoided when developing feeding protocols for mixed species exhibits. 6 These should incorporate the specific needs and required feeding supplementations of the various species in a mixed exhibit.

Various herpesviruses are known to be responsible for disease outbreaks in mixed species exhibits. Other viruses such as rabies or bacteria (e.g., Mycobacterium tuberculosis complex) or a variety of endoparasite, ectoparasite, or fungal infections (e.g., aspergillosis) may each be detrimental in mixed exhibits, because not only one species will be infected, as in single-species exhibits. Measures to control these diseases may have an enormous impact on a collection and demands for an effective preventative veterinary protocol. Decisions about which species are to be housed together should be made based on this information. , and banteng (Bos javanicus) are especially susceptible to these diseases. 4, 5 In white-tailed deer (Odocoileus virginianus), a new MCF virus has been recognized that causes classic MCF. Do not mix wildebeest with giraffes and preferably get rid of all sheep and goats in a zoo collection. Carrier species should at least not be in breeding situations in direct contact or close to susceptible species. There are examples of zookeepers owning sheep at home that transmitted the virus to giraffes, resulting in high mortality. 7 It is questionable whether zookeepers should be allowed to take care of household sheep and goats at home. exhibits so animals may circle around these when chased, hiding places, and provision of multiple feeding and watering sources are workable preventive measures when planning mixed exhibits. 6 There is no definition of an appropriate size, but for animal welfare reasons and to avoid trauma, exhibits should be as large as possible.

Adequate nutrition is vital for every living being. In mixed exhibits, a sufficient number of feeding stations is essential to ensure that all animals may eat and at the same time prevent that some don't overeat. 6 Also, to prevent interspecies aggression, a sufficient number of feeding stations is necessary. Spreading food over larger areas in aviaries or among hoofstock prevents aggressiveness, and is even more effective when food is provided several times a day.

Free-flying wild birds may be a nuisance when feeding, such as kangaroos and birds (e.g., storks and cranes). A special configuration of feeding places may be helpful to prevent this. Precautions should be taken to prevent animals from not being able to eat enough and losing too much weight.

Requirements of trace minerals and other nutrients such as vitamins differ among species. Deficiencies such as copper deficiency in blesbok (Damaliscus pygargus species. There are many carriers of these viruses. Coronaviruses are also known to cause winter dysentery in adult ruminants. 6

Spider monkeys (subfamily Ateles) and squirrel monkeys (Saimiri sciureus) should not be placed in mixed exhibits with other primates. Squirrel monkeys are hosts of two herpesviruses (Herpesvirus tamarinus, H. saimiri) and spider monkeys may transfer H. ateles to callitrichids, aotids, marmosets, and tamarins, causing fatal disease in these species. 6 Rhesus macaques (Macaca mulatta) and other macaques may host H. simiae (HVB or, most recently, cercopithecine HV-1) and is transmitted by biting and scratching and by dried secretions-for example, to Colobus monkeys (Colobus guereza). 6 Do not mix African and Asian monkeys. At least, macaques should be seronegative for HVs when housed in mixed exhibits. Another herpesvirus, the simian varicella group (SVV), is hosted by macaques; it produces mild, self-limiting signs in the host species but may be fatal in patas monkeys (Erythrocebus patas) and other African cercopithecines. Simian hemorrhagic fever (SHF) and simian immunodeficiency virus (SIV) are other reasons not to mix African and Asian monkeys, because they will spread among these primates.

In mixed primate exhibits, salmonellosis, campylobacteriasis, bordetellosis, and shigellosis should be monitored as preventive measures. 4

In marine mammals (cetaceans, pinnipedia), Morbillivirus, Orthopoxvirus, and Parapoxvirus infections may occur when water systems are connected between basins. 6 The Morbillivirus outbreak in the north of the Netherlands, Germany, and Denmark has shown that vaccination using canine distemper virus (CDV-ISCOM) (immunestimulating complex) vaccine is effective in protecting harbor seals (Phoca vitulina) from phocid distemper in 1988. This vaccine from Erasmus University, Rotterdam, The Netherlands, halted the spread of the disease. Using inactivated canine distemper virus will do the same, but is not allowed for use in the European Union (EU).

Avian herpesviruses such as the Pacheco disease virus may be carried by conures and should be taken into Equine herpesvirus 1 has led to problems with Bactrian camel (Camelus bactrianus), llama (Lama glama), and a Thompson's gazelle (Gazella thomsoni). 6 The virus is shed by infected horses (Equus caballus), zebra (E. grevyi, E. zebra, E. quagga), and onager ( E. hemionus) during respiratory infection, parturition, and abortion. Vaccination is no guarantee for preventing an outbreak. When introducing equids into mixed exhibits, it is advisable to use only seronegative equids.

Mixed exhibits with ruminants should be monitored serologically for diseases such as leptospirosis, brucellosis, infectious bovine rhinotracheitis (IBR; bovine herpesvirus 1 [BHV-1]), bovine virus diarrhea (BVD), tuberculosis (Mycobacterium tuberculosis, M. bovis), paratuberculosis (M. avium subsp. paratuberculosis), leucosis (enzootic bovine leucosis, bovine leukemia virus), neosporosis (Neospora caninum), bovine respiratory syncytial virus (BRSV; e.g., ovine lentivirus, Maedi-Visna)because most of these diseases spread between different ruminant species. Brucellosis, leptospirosis, and tuberculosis will also affect numerous other mammalian species. 4 The following are other mammalian diseases 4 4 Mycobacteriosis in the form of paratuberculosis or the mycobacteriaceae responsible for the tuberculosis complex are not easy to control in mixed species exhibits.

Bacterial infections such as leptospirosis, erysipelas, listeriosis, pseudomoniasis, and infections caused by enterobacteria and Clostridia are found in many species. They are responsible for an enormous variety of disease problems, especially in mixed species exhibits. 4 Almost all notifiable diseases as listed in 

Many parasites have a broad host range and are a threat in mixed species exhibits. One animal imported into a collection may be hazardous not only to its own species, but also other species in mixed species exhibits.

Protozoal parasites easily contaminate exhibit substrates. Preventive protocols should be taken to avoid serious problems. In mixed primate exhibits, various protozoal infections may be seen and may cause problems such as gastric amoebiasis, giardiosis, hexamitiasis, trichomoniasis, and cryptosporidiosis. It is popular to mix gorillas in exhibits with other African species such as Colobus monkeys (C. guereza) and mangabeys ( Fig.  4-7) . However, be careful when mixing them, because cercopithecine monkeys are often carriers of Balantidium coli. All great apes, especially gorillas, may become very ill from these infections. 4, 6 Toxoplasmosis may be found in all vertebrates and may be spread by all felid species. In mixed aviaries, Trichomonas spp. are common in columbiforms but may spread to passeriforms or psittacines, who may become seriously ill. 6 Puffins and penguins are very susceptible to Plasmodium infections causing avian malaria. The infection is endemic in many continental birds in Europe and North America and, from these carrier birds, the disease is spread to the susceptible penguins and puffins by mosquito vectors. Antimalarial drugs as a preventive measure are widely used in these birds. Another protozoal parasite, Neospora caninum, causes abortions in some herbivores.

Endoparasites such as nematodes, trematodes, and cestodes should also be monitored in mixed species account when mixing birds; they may cross to different species and cause devastating outbreaks in other species of psittacine birds. 6 Avipoxvirus infections are seen in mixed aviaries because a variety of birds are susceptible to the virus. 4

Tortoises are also known for herpesviruses that will spread among different species. Some species act as reservoirs, whereas other species show high mortality. 6 Another herpesvirus causing fibropapillomatosis is seen in various marine turtles. 4 Gray patch disease in marine turtles is probably also caused by a herpesvirus. It requires the same strict regimen of hygienic measures and quarantine as the other herpesviruses when mixing these animals.

Ophidian paramyxovirus may be transmitted between snakes. Viperids show a variety of susceptibility to this virus and may infect other groups of snakes, such as boids, elaphids and colubrids. 4 Mixed exhibits of amphibian species may have an extra chance of outbreaks of chytridiomycosis caused by Batrachochytrium dentrobatidis. Frogs, toads, salamanders, and others are susceptible. In amphibians, the spread of adenovirus infections among lizards, snakes, and crocodiles may only be prevented by in-house biosecurity measures.

West Nile virus (WNV) is a vector-borne disease noted in almost 300 species of birds and a variety of domestic and exotic mammals. Using the U.S. data acquired after the WNV outbreak in recent years, vaccination protocols and vector control should be proactively discussed before WNV becomes endemic in Europe. 4 Salmonella spp. (especially S. typhimurium and S. enteridius) in mixed bird exhibits and in reptile departments in zoos are difficult to control. Also, among mammals, different Salmonella spp. may result in high morbidity and mortality. 4 Yersinia pseudotuberculosis and Y. enterocolitica are responsible for mortality in various species of birds, rodents, and primates (e.g., squirrel monkeys, Saimirinae). Often, transmission occurs through uninvited vector species (e.g., rats, mice, wild birds) who share a mixed exhibit with collection species. 4 Chlamydophila psittaci affects psittacines, passerines, and columbiformes. This well-known zoonosis may also cause significant infections in other nonavian species. 4 Fungal diseases are seen in all taxa. Trichophyton spp., Microsporum spp., aspergillosis, candidiasis, Malassezia, exhibits because many of them cross species lines. Every large animal practitioner knows not to keep horses and donkeys together-donkeys are carriers of lungworms, without clinical problems, but horses are vulnerable to these parasites. Mixing a variety of artiodactylids will lead to a burden of possible parasitical infections, especially enteric nematode infections. 6 In mixed aviaries, helminths are potentially lethal among birds (especially Capillaria spp. and Syngamus trachea) and preventive measures are a necessity.

Ectoparasites such as Sarcoptes and Chorioptes spp. are capable of affecting different, often related species and are not always easy to control in larger mixed species exhibits. 

Transmissible diseases handbook: European association of zoo and wildlife veterinarians

GVP (good veterinary practice) regarding (emerging) infectious diseases-a political issue? Presented at the 7th Scientific Meeting of the European Association of Zoo and Wildlife Veterinarians

European Association of Zoo and Wildlife Veterinarians-Infectious Diseases Working Group

Malignant catarrhal fever in two closely related zoos in The Netherlands

Health problems in mixed-species exhibits