Zoonotics

The use of weapons of mass destruction by international terrorist organizations remains a potential threat. But in my opinion this is not the major risk to the public at large. Biological weapons of mass destruction such as anthrax or other pathogens are relatively difficult to stabilize, transport, and effectively disseminate on a large scale.

Whereas there are some agents which are easy to stabilize and simpler to transport known as zoonotic agents. Zoonotics was derived from two words “zoon + noses”. Zoon means animals and noses means diseases. (1,2)

The World Health Organization defines Zoonoses (Zoonosis, sing.) as "Those diseases and infections which are naturally transmitted between vertebrate animals and man". They demonstrate the ability to infect humans and animals. Numerous organisms have zoonotic potential of which many are devastating and horrible diseases. Both dogs and cats are born with lots of worms that go dormant in their muscle tissue and emerge throughout the pet's life during periods of stress (especially pregnancy) or sickness. Therefore even pets, without exposure to other pets, can turn up positive for worms after previously being tested as negative on a fecal exam. In addition, they continuously pick up microscopic worm eggs in the environment. The worms go through their life cycle in the dog or cat, causing various degrees of trouble to the pet and end up spreading more worm eggs via the stool.

People can also pick up these worm eggs and transmit them accidentally to their mouth. Luckily, most of us have a healthy immune system and the worms in dogs and cats are usually successfully killed soon after entering our bodies but not always. This may be one of the causes of unexplained fevers, aches and pains that people suffer from for a couple of days and we often call "a touch of flu". Sometimes worms can cause much more serious trouble in humans, especially to a developing fetus or children. A more serious way that people get worm diseases from pets is from eggs in the yard or sandbox that hatch into larvae that can bore into skin and travel around in your blood, lymph, or neural system causing anything from mild rashes to blindness and other terrible disease. This is a problem with barefoot children, especially if the ground is damp which favors larval hatching. This disease is known as larval migrans.

Classification of zoonotics (3,5,6)

A classification system based on the type of life cycle of the infective organism seems the most useful in planning a preventive medicine program. The following categories are recommended by the World Health Organization Expert Committee on Zoonoses:

1. Direct Zoonoses: Transmitted from infected vertebrate host to a susceptible vertebrate host by direct contact, fomite, or by a mechanical vector. No developmental change or propagation of the organism occurs during the transmission. Examples: Rabies, trichinosis, and brucellosis.

2. Cyclozoonoses: Requires more than one vertebrate host, but no invertebrate host. Examples: Human taeniasis, echinococcosis, and Pentastoma infections.

3. Metazoonoses: Agent multiplies, develops, or both in an invertebrate host before transmission to a vertebrate host is possible. (This means that a definite prepatent or incubation period must be completed before transmission.) Examples: arboviruses, plague, and schistosomiasis.

4. Saprozoonoses: To transmit these infections a non-animal development site or reservoir is required, such as food plants, soil, or other organic material. Examples: larva migrans and some of the mycotic diseases.

Mode of transmission (7,13,19)

· FECES

· URINE

· SALIVA

· BLOOD

· MILK via aerosol, oral, contact with bedding or animals, etc.

Types of Diseases and causative agents (23)

PARASITIC (Internal)

• Visceral larval migrans (roundworms) - fecal transmission - contracted by eating grass or mouthing toys, rocks, etc. in infected areas.
• Cutaneous larval migrans (hookworms) - fecal transmission - contracted by simply walking through an infected area (larva can burrow into dog footpads).
• Dipylidiasis (tapeworm-Dipylidium Caninum) - fecal transmission - primarily carried by fleas. As a precaution, dog should be wormed after a flea infestation.
• Echinococcosis (tapeworm-Echinococcus Granulosus) - fecal transmission - also carried by fleas.
• Dirofilariasis (heartworm) - blood transmission - carried by mosquitoes, astonishingly high occurrence in certain areas of the country.
• Giardiasis (Giadaria) - fecal transmission - protozoan that lives in deep well high mountain water. It causes moderate to severe diarrhea in both dogs and humans.
• Cryptospordidiosis (Cryptosporidia) - fecal transmission - causes diarrhea fever.

ECTOPARASITES (External)

• Rocky Mountain Spotted Fever - tick borne bacteria - dog will be feverish and disoriented, with an area of swelling near where the tick attaches.
• Plague - flea borne* - dog will be feverish and lethargic. Plague is carried by fleas but may also be contracted by contact with an infected rodent.
• Lyme Disease  - tick borne bacteria* - symptoms include swollen joints, difficulty in moving, and fever. (11)

BACTERIAL Infections

• Brucellosis - sexually transmitted ONLY
• Leptospirosis - vaccination available through your veterinarian.
• Camphlobacteriosis and Salmonellosis (Salmonella) - fecal transmission - acquired by ingesting and contaminated food.

MYCOTIC Diseases (Fungus)

• Dermatomycosis (Ringworm) - skin infection that looks like worms under the skin, but is actually a fungus.
• Sparotrichosis - Fungus infecting open wounds

VIRUSES

• Rabies - vaccination available through your veterinarian.

Precautions

"Clean hands are the single most important factor in preventing the spread of dangerous germs and antibiotic resistance in health care settings" (16,21)

More widespread use of these products that improve adherence to recommended hand hygiene practices would promote patient safety and prevent infections. Improved adherence to hand hygiene (i.e. hand washing or use of alcohol-based hand rubs) has been shown to terminate outbreaks in health care facilities, to reduce transmission of antimicrobial resistant organisms (e.g. methicillin resistant staphylococcus aureus) and reduce overall infection rates. (15) Handwashing with soap and water remains a sensible strategy for hand hygiene in nonhealth care settings and is recommended by experts. The use of gloves does not eliminate the need for hand hygiene. Likewise, the use of hand hygiene does not eliminate the need for gloves. Gloves reduce hand contamination by 70 percent to 80 percent, prevent cross-contamination and protect patients and health care personnel from infection. Handrubs should be used before and after each patient just as gloves should be changed before and after each patient. (21,22)

Alcohol-based handrubs significantly reduce the number of microorganisms on skin, are fast acting and cause less skin irritation. Alcohol-based hand rubs take less time to use than traditional hand washing. In an eight-hour shift, an estimated one hour of an ICU nurse's time will be saved by using an alcohol-based handrub. This problem is controlled by keeping pet stool picked up and mostly from regularly deworming your pets. (18.20) Get your worm control products only from a doctor because many products sold elsewhere don't work very well. This is due to resistance from the worms and for legal reasons. Another thing to know is that if a pet bites you; first wash out the bite wound well (the rabies virus is killed by most antiseptics), and if you're not sure if the animal that bit you has a current rabies vaccination, call a physician. And most of all, Be careful in handling wild animals. The biggest carriers of rabies are foxes, coons, skunks, woodchucks, squirrels, feral cats, and bats. This advice is especially important to all of you kindhearted people that rescue injured and sick wild animals and try to catch wild cats. Be careful out there.

References

1. Acha, P.N. and Szyfres, B.: Zoonoses and communicable diseases of man and animals. Pan American Health Organization, Washington, DC, 1987.
2. August, J.R.: Zoonotic complications of bite and scratch wounds. Proceedings of the 10th ACVIM Forum.665-667, 1992.
3. Bell, J.C., Palmer, S.R., and Payne, J.M.: The zoonoses: infections transmitted from animals to man. Edward Arnold Press, London, UK, 1988.
4. Benenson, A.S.: Control of Communicable Diseases in Man (15th ed.). American Public Health Association, 1990.
5. Chomel, B.B.: Zoonoses of house pets other than dogs, cats, and birds. The Pediatric Infectious Disease Journal. 11(6): 479-487,1992.
6. Fox, J.G. and Lipman, N.S.: Infections transmitted by large and laboratory animals. Infectious Disease Clinic of North America. 5(1): 131-161,1991.
7. Fox, J.G., Newcomer, C.E., and Rozmiarek, H.: Selected zoonoses and Other Health Hazards. In "Laboratory Animal Medicine" (J.G. Fox et.al.). Academic Press, Orlando. 613-648,1984.
8. Goldstein, E.J.: Management of human and animal bite wounds. J Am Acad Dermatol. 21(6): 1275-9,1989.
9. Goldstein, E.J.: Household pets and human infections. Infectious Disease Clinics of North America. 5(1): 117,1991.
10. Lappin, M.R.: Feline zoonotic diseases. Veterinary Clinics of North America: Small Animal Practice. 23(1): 57-79,1993.
11. Madigan, J.E.: Lyme disease update. Proc. 10th ACVIM Forum. 692-8,1992.
12. Marx, M.B.: Parasites, pets, and people. Primary Care. 18(1): 153-165,1991.
13. Meslin, F.X.: Surveillance and control of emerging zoonoses. World Health Stat Q. 45(2-3): 200-207,1992.
14. Steele, J.H.: Handbook Series in Zoonoses. Section A: Bacterial, Rickettsial, and Mycotic Diseases (Vol I), CRC Press, Boca Raton, 1979.
15. Steele, J.H.: Handbook Series in Zoonoses. Section A: Bacterial, Rickettsial, and Mycotic Diseases (Vol II), CRC Press, Boca Raton, 1980.
16. Viral Steele, J.H.: Handbook Series in Zoonoses. Section B: Viral Zoonoses (Vol I), CRC Press, Boca Raton, 1981.
17. Viral Steele, J.H.: Handbook Series in Zoonoses. Section B: Viral Zoonoses (Vol II), CRC Press, Boca Raton, 1981.
18. Wood, D.H.: Selected Topics in Laboratory Animal Medicine: Zoonoses of Nonprimates. In "Aeromedical Review" (USAF School of Aerospace Medicine), AFSC, Brooks Air Base, TX .1-28,1973.
19. http://www.AnimalPetDoctor.com
20. http://www.utskinvet.org/
21. http://www.cdc.gov/drugresistance/community/faqs.htm#facts
22. http://www.cd c.gov/od /oc/media/pressrel/fs021025.htm
23. http://research.ucsb.edu/connect/pro/disease.html

*Sumit Khanna, Department of Pharmaceutical Sciences, G. J. University, Hisar-125 001 

397,Sec-13, Hisar, Haryana, India

GSM: +919416045445

E-mail: sumKhanna@hotmail.com