Zoonotic Diseases An Overview

Zoonotic Infections From the Greek: Zoonosis Zoo: Animal Nosos: Disease

Zoonotic Pandemics In 1700 century, Mongols invaded Europe and carried plague with them. This lead to “black death” or plague pandemic which Killed 1/3 of European population. Early 1900 century “Spanish flu” transmitted from pigs to humans. killed 20 million people worldwide. Still continues to pose a threat to humans.

Zoonoses and communicable diseases: Any disease or infection that is naturally transmissible from vertebrate animals to humans and vice-versa is classified as a zoonosis according to the PAHO publication "Zoonoses and communicable diseases common to man and animals". Zoonoses have been recognized for many centuries, and over 200 have been described. They are caused by all types of pathogenic agents, including bacteria, parasites, fungi, and viruses. (WHO)

Factsheet Zoonotic diseases can be caused by viruses, bacteria, parasites, and fungi. Scientists estimate that more than 6 out of every 10 infectious diseases in humans are spread from animals. Many people interact with animals in their daily lives. We raise animals for food and keep them in our homes as pets. There are over 200 zoonotic diseases. The major zoonotic diseases WHO deals with are Anthrax, CCHF, Rabies, Animal Influenza. (CDC)

Classification Some examples of zoonoses, classified according to the type of causative agent, are given hereafter. Bacteria Viruses Parasites Fungi

Transmission Because of these interactions, it’s important to be aware of the different ways people can get zoonotic diseases. These can include: Coming into contact with the saliva, blood, urine, or feces of an infected animal Being bitten by a tick or mosquito (often called a “vector”) Eating or drinking something unsafe (such as unpasteurized milk, undercooked meat, or unwashed fruits and vegetables that are contaminated with feces from an infected animal)

Avian influenza Avian influenza (AI), commonly called bird flu, is an infectious viral disease of birds. Most avian influenza viruses do not infect humans; however some, such as A(H5N1) and A(H7N9), have caused serious infections in people. Outbreaks of AI in poultry may raise global public health concerns due to their effect on poultry populations, their potential to cause serious disease in people, and their pandemic potential. Reports of highly pathogenic AI epidemics in poultry, such as A(H5N1), can seriously impact local and global economies and international trade. The majority of human cases of A(H5N1) and A(H7N9) infection have been associated with direct or indirect contact with infected live or dead poultry. There is no evidence that the disease can be spread to people through properly cooked food. Controlling the disease in animals is the first step in decreasing risks to humans

Rabies Rabies is a disease that affects the nervous system of mammals. It is caused by a virus and is typically spread by an infected animal biting another animal or person. Rabies is a fatal disease; it cannot be treated once symptoms appear. Luckily, rabies can be effectively prevented by vaccination

Crimean-Congo hemorrhagic fever (CCHF) Crimean-Congo hemorrhagic fever (CCHF) spreads to humans either by tick-bites, or through contact with viraemic animal tissues during and immediately post-slaughter. CCHF outbreaks constitute a threat to public health services because of its epidemic potential, its high case fatality ratio (10-40%), its potential for nosocomial outbreaks and the difficulties in treatment and prevention. CCHF is endemic in all of Africa, the Balkans, the Middle East and in Asia south of the 50° parallel north, the geographic limit of the genus Hyalomma, the principal tick vector.

What kind of animals transmit zoonoses? Farm Animals Cattle Swine Goats Cats & dogs Poultry

Wild animals Ticks Squirrels Mice/rats

Global early warning system GLEWS is a joint system that builds on the added value of combining and coordinating alert mechanisms of the Food and Agriculture Organization of the United Nations (FAO), the World Organization for Animal Health (OIE) and WHO. Networks from the international community and stakeholders are linked to assist in early warning, prevention and control of animal disease threats, including zoonoses

Characteristics Of Zoonotic Diseases Acute diseases; severe and of short duration. Chronic Diseases; long lasting.

Prevention

Assure an uncontaminated water supply Properly construct wells Add chlorination to water Appropriate disposal of wastes

Prevent food contamination Avoid unpasteurized milk. Wash hands before and after eating. Always disinfect kitchen surfaces. Wash raw fruits and vegetables. Don’t defrost meats on the counter.

Cooking guidelines Cook meats until juices are clear. Poultry – internal temp of 180 degrees. Beef – internal temp of 160 degrees. Cook eggs until firm. Avoid foods with partially cooked eggs.

Storing leftovers Store food in appropriate containers. Set refrigerator temp to 4 degree C and freezer to 0 degree C. Refrigerate leftovers immediately. Never leave food out for more than 2 hours.

Avoid contact with diseased animals Spray animals Apply DEET lotion while touching animals. Wear appropriate clothing and gloves. Avoid direct blood contact specially when you have wound/infection. Dispose of carcasses properly. Wash hands afterwards.

Protect Pets From Getting & Transmitting Diseases Visit your veterinarian with your pet on a regular basis and keep rabies vaccinations up-to-date for all cats and dogs. Maintain control of your pets by keeping cats indoors and keeping dogs under direct supervision Always keep clean pet’s and their living area.

Prevent tick bites Use repellents that contain 20 to 30% DEET (N, N-diethyl-m-toluamide) on exposed skin and clothing for protection that lasts up to several hours. Always follow product instructions. Parents should apply this product to their children, avoiding hands, eyes, and mouth. Wear appropriate clothing. Long-sleeved shirt. Wearing socks. Bath or shower as soon as possible after coming indoors (preferably within two hours) to wash off and more easily find ticks that are crawling on you.

Treat animal scratches and bites seriously Wash area with soap and water. Apply anti-bacterial medication. Bandage wound. Consider medical attention.

Most Zoonoses are preventable if cautionary measures are taken!!

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