Zoonotic Diseases

What is Q fever and how is it managed in the workplace?

Zoonotic diseases

Zoonotic diseases are diseases that may be contracted from animals and animal products. Zoonotic diseases include Brucellosis, Leptospirosis, Q fever, Hydatid disease, Erysipeloid and Orf. The three principal diseases of concern are Q fever, Leptospirosis and Brucellosis.

How is Q fever contracted?

Q fever is the most likely disease to be contracted from animals or animal products. People can be infected by close contact with any material contaminated with the Q fever bacteria. It may be contracted from foetuses, placenta, faeces and milk of infected cattle, sheep and goats. Inhalation of contaminated aerosols or dust is the most common form of transmission. Q fever can also be passed on by contact with infected animals and contaminated articles such as straw, wool, hair and hides.

An individual who has not developed an immunity to Q fever, either naturally or by immunisation, is at risk of becoming infected. Those most at risk of becoming infected will be new workers to the industry and visitors to sites.

Signs and symptoms of Q fever

The time between breathing in the organism and the onset of the illness is generally 19–21 days.

Many of the symptoms of Q fever are typical of influenza, so it may be misdiagnosed. The symptoms include fever, sweats, severe headaches, myalgia, fatigue, nausea and photophobia and weight loss.

For some there is no illness, for others it is like a bad dose of the flu.

A smaller number of people may develop more severe or debilitating illness following initial Q fever infection. As many as 10-20% of people with acute Q fever illness may go on and develop signs of chronic fatigue called Post Q Fever Fatigue Syndrome (QFS). A smaller number of people may develop severe illness such as pneumonia or endocarditis and other conditions.

Treatment

Appropriate antibiotics, commenced soon after the onset of the illness, may be useful to improve recovery. Prolonged therapy may be required for chronic disease.

Prevention- vaccination against Q fever

The most effective control measures for Q fever is pre-screening and vaccination program for every person entering the premises of meat processing plants.

Every meat processing plant in Australia provides Q fever vaccination for workers. Generally no-one is allowed on plant without Q fever vaccination. As trainees or workers you should not enter the plant without being vaccinated against Q fever.

Before vaccination, people must have skin and blood tests to check if they have previously been infected with Q fever. Immunity to Q fever typically develops 15 days after vaccination.

Note that Q fever vaccine should not be given to people who have previously had Q Fever or who have tested positive on skin or blood tests, people who have previously been vaccinated against Q fever, people with known hypersensitivity to egg proteins, pregnant women and children younger than 15 years of age.

Follow good hygiene practices

People working with animals or materials that may carry the Q Fever bacteria should be aware of general principles of infection control through practising good hygiene practices including handwashing, cough hygiene and not touching the face. They should also use effective personal protective equipment where appropriate and avoid or minimise risks of exposure to potentially infective material.

For more detailed information on the symptoms and complications see the Q Fever Information Kit for the Australian Meat Processing.

What can be done to minimise the risk of contracting a zoonotic disease?

Leptospirosis

Leptospirosis may be contracted through direct contact with infected urine of infected cattle, pigs and horses. The leptospirosis organism can enter the body via eyes, mouth and damaged skin.

Brucellosis

Brucellosis may be contracted by direct or indirect contact with infected material from foetuses, placenta, faeces, raw flesh and milk of infected cattle, goats and feral pigs. Cattle are declared brucellosis free in all states except the Northern Territory. The organism may enter the body via the skin, eyes, mouth and by breathing in infected dust and aerosols.

Risk control program

Employers are required by law to reduce risks to the lowest possible levels. Zoonotic diseases have the potential to cause harm to meat processing workers. Employers should have a risk control program in place to minimise the risks to workers of exposure to zoonotic diseases. The risk control program involves identifying the situations that may lead to exposure to potentially infective material such as body fluids of sheep, cattle and goats and introducing controls to reduce or eliminate exposure of workers to these materials.

Ideally the control measures focus on eliminating exposre to potentially infected materials through engineering controls such as:

• ventilation, exhaust and air conditioning system are installed
• chutes for offal, slinks and carcase remnants are properly fitted with flaps or covers
• the plant, including yards, pens, rendering areas and skin sheds are designed and maintained to ensure easy cleaning and efficient quick drainage
• areas readily accessed by workers or visitors, for example the canteen, are not positioned near the yards or exposed to air ducted from the slaughter floor or condemned room.

It is also critical that workers follow work practices that reduce the risk of contamination and infection. This may be achieved by measures such as:

• washing stock down on the race entering the slaughter floor
• improving methods of handling animals
• careful removal of the paunch, stomachs, etc. to ensure they do not burst
• lowering of the guts to the eviscerating table to maintain the integrity of the released organs
• the early removal of any type of contaminant from carcases
• prohibiting the storage of personal and soiled work clothing together in lockers
• laundering of work clothing by the employer
• muzzling of dogs used to move livestock
• no eating, drinking, smoking or nail biting in stock holding or processing areas.
• workers wearing personal protective equipment where appropriate to avoid or minimise risks of exposure to potentially infective material.

Access to the workplace should be strictly restricted to workers required to be there. Non-essential visitors, for example school, university or tour groups, should be discouraged as they may not have immunity to Q fever. Proof of vaccination or existing immunity is now a pre-requisite by some plants before allowing entry to contractors and regular visitors. If access is permitted without proof of immunity, appropriate respiratory protection is recommended.