Care and Use of Animals

Zoonotic Diseases


Dogs

Rabies: The incidence of rabies in wildlife in the United States has increased in recent years and there is a possibility of transmission to dogs and cats with uncertain vaccination history. Rabies is very rare in the laboratory environment but any random source animal or wild animal showing central nervous system signs must be considered a potentially rabid animal. The rabies virus is most commonly transmitted to other animals or humans by the bite of a rabid animal or by introduction of saliva containing the virus into skin wounds or intact mucous membranes. Rabies produces a fatal acute viral encephalomyelitis.

Prevention: Pre-exposure immunization should be available to personnel working with or caring for animals of uncertain vaccination status or those who work with wildlife known to be reservoirs of rabies.

Brucellosis: B. suis is the species of Brucella that infects swine and B. canis infects dogs. Transmission to humans has resulted from contact with aborted tissues and placentas from infected animals. Symptoms in humans are fever, headache, chills, myalgia, nausea, and weight loss.

Prevention: Preventive measures include testing and eliminating infected animals from research facilities. Persons working with potential or known positive animals should practice good personnel hygiene to include hand washing after handling animals. Protective clothing should also be worn.

Cryptosporidia: Cryptosporidium species have a worldwide distribution and can be found in many animal species including cats. Cryptosporidiosis is caused by protozoan parasites that live in the intestines of mammals. Cryptosporidiosis is transmitted by the fecal-oral route and can cause diarrhea in humans. Usually the diarrhea is self-limiting but in immunocompromised individuals the disease can have a prolonged course.

Prevention: Appropriate personal-hygiene practices which include washing hands after contact with animals or their waste should prevent spread of this organism.

Giardia: Giardia species are present in wild animals and laboratory animals, including dogs and cats. Giardia is transmitted via the fecal-oral route. Human infection can be asymptomatic or cause nausea, abdominal cramping, and intermittent diarrhea.

Prevention: Good personal hygiene which includes hand washing after contact with animals or their waste will help prevent spread of this organism.

Campylobacter: Campylobacter species can be found in pet and laboratory animal species. Transmission to humans is by the fecal-oral route and can produce an acute enteritis. Symptoms include diarrhea, abdominal pain, fever, nausea, and vomiting.

Prevention: Use of personal protective clothing, good personal hygiene, and sanitation measures will help to prevent the transmission of the disease.

Salmonellosis: Along with a variety of other species, Salmonella, and other enteric bacteria are capable of causing disease in humans. Salmonellae are transmitted by the fecal-oral route. Infection produces an acute enterocolitis and fever with possible secondary complications such as septicemia.

Prevention: Use of protective clothing, personal hygiene which include hand washing after contact with animals or their waste, and sanitation measures prevent the transmission of the disease.

Ringworm: Dermatophytes, which are fungi, cause ringworm in humans and animals. Infection in animals may be inapparent and is transmitted to humans by direct contact with infected animals or by indirect contact with contaminated equipment or materials. Dermatophytes produce flat, circular lesions that are clear in the center and crusted and red on the periphery.

Prevention: The use of protective clothing, disposable gloves, and hand washing along with good personal hygiene will help to reduce the spread of dermatophytosis in a laboratory animal facility.

Ascariasis: Toxocara canis, the dog ascarid or round worm, is a cause of larva migrans syndromes in children. The ascarid of cats, Toxocara cati, is also capable of causing disease in humans. When eggs of either species are accidentally ingested, they will hatch and the infective stage larvae will migrate outside of the intestinal tract (larva migrans). Liver, lungs and other organs and tissue can be permanently damaged by the migrating larvae. Infected children may be left with permanent vision or neurologic damage.

Prevention: Appropriate testing and treating of research dogs and cats for intestinal parasites will prevent the spread of ascarid between animals and lower the risk for personnel. Good personal hygiene to include hand washing after contact with dogs and cats and their waste will help prevent this disease in humans.

Hookworms: Ancylostoma caninum, Ancylostoma braziliense, Ancylostoma tubaeforme and Uncinaria stenocephala, are the hookworms of dogs and cats. People can also become infected when the larvae in soil or on other surfaces are ingested or directly penetrate the skin. These parasites then migrate under the skin creating cutaneous larva migrans syndromes characterized by pruritic, linear eruptive lesions. A. canium larvae are capable of penetrating into other tissues and inducing symptoms of visceral larva migrans or can migrate and mature in the intestine and cause an enteritis.

Prevention: Appropriate testing and treating of research dogs and cats for intestinal parasites will prevent the spread of hookworms between animal and lower the risk for personnel. Good personnel hygiene to include hand washing after contact with animals or their waste will help prevent disease in humans.

Leptospirosis: Leptospirosis is widely distributed in domestic and wild animals. The possibility of transmission to humans from most animal species maintained in the laboratory should be considered but livestock and dogs would be the most common reservoirs. Transmission of the organism to humans can occur through skin abrasions and mucous membranes by contact with urine or tissues of animals infected with Leptospirosis. Inhalation or ingestion of organisms can also transmit the diseases. Disease can vary from asymptomatic infection to severe disease ranging from flu-like symptoms to liver and kidney failure, encephalitis, and pulmonary involvement.

Prevention: Control of this infection in laboratory animal populations along with use of protective clothing and gloves by persons working with and caring for infected animals will help prevent disease.

References:

Risk assessment- UC Davis
http://ehs.ucdavis.edu/animal/risk/index.cfm

Occupational Health and Safety in the Care and Use of Research Animals, National Research Council; National Academy Press, 1997.

Center for Disease Control- Division of Bacterial and Mycotic Diseases
http://www.cdc.gov/ncidod/dbmd/

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