Cats and Q-fever
I was reading an interesting old paper the other day about Q-fever in cats. Q-fever is a zoonotic disease caused by Coxiella burnetii. It is most commonly associated with contact with sheep, cattle and to a lesser extent goats, around the time they give birth. This bacterium is highly infectious - it only takes a small number of bacteria to cause disease. (That's one of the reasons it's classified as an important bioterrorism agent).
While most of the focus in on ruminants, there have also been many reports of Q-fever associated with cats, also mainly through contact with these animals around the time they give birth. Cats may be the most important Q-fever reservoir in urban areas.
The study I was reading, a 1988 article from the journal Chest, describes a Q-fever outbreak in a town in Nova Scotia. Thirty-three people were infected in the town of Baddeck (population 900, meaning 2.8% of the population was affected). Forty-two percent of infected individuals lived in four side-by-side buildings. Investigation revealed that most infected people had contact with a cat that have given birth to stillborn kittens (stillbirths are common in cats infected with Coxiella). The cat lived in one of the four buildings and regularly visited neighbouring buildings.
This is just one of many reports of Q-fever associated with cats. Almost all involve direct contact or being in the vicinity of cats around the time of birth. Since this bacterium is so infectious, and can even be spread through the air through aerosols (e.g.dust, tiny droplets of fluid), direct contact (e.g actually touching the cat) is not required for infection to occur.
That being said, cat-associated Q-fever is probably still pretty uncommon, but Q-fever can be a very serious disease. Since transmission mostly involves cats at the time of birthing, a few basic measures should be able to greatly reduce the risks:
- Avoid contact with cats that are giving birth or who have done so recently.
- Avoid contact with newborn kittens and areas contaminated during the birthing process.
- If your cat is going to give birth, try to have it do so in a well-ventilated area away from areas where people spend time and away from areas where food is prepared.
- If contact with the mother cat, kittens or areas/items contamination with birth fluids is likely to occur, gloves should be worn. Hands should be washed after gloves are removed.
- If a cat gives birth inside, the area should be thoroughly cleaned and disinfected afterwards. Gloves should be worn for this.
- The risks are probably higher with stray cats (who are more likely to be infected), so extra care should be taken to avoid contact with stray cats around the time of birth.
More information about Q-fever can be found in the Worms & Germs archives.
Doctors, pets and vets
Over 50% of households in Canada and the US have pets, and the numbers are probably similar in many other countries. Pets are often considered part of the family socially but we need to consider them part of the family biologically as well. It's clear that diseases that be transmitted between people and pets - in both directions. Unfortunately, it's also clear that physicians and vets don't do a very good job talking to each other.
Pet contact (and animal contact, in general) should be part of the standard history obtained by any physician. In my perfect world, every medical record would include a permanent record of contact with pets or other animals. This information is potentially useful because certain diseases that are not a big issue for non-pet owners may need to be considered (or may be higher on the list of possibilities) in pet owners. Knowing about pet contacts up front could help speed up diagnosis and proper treatment.
For example:
I have a flock of rare breed sheep. The other day, I had to assist with a lambing. Contact with newborn lambs and fetal fluids is the main source of the organism Coxiella burnetti, which causes Q-fever. If I became infected, the illness would start off with vague signs like fever and malaise. If I went to a physician at that point, I'd probably be told to go home, rest and take anti-inflammatories as needed (the old "take two aspirin and call me in the morning" type thing). If the physician knew I had sheep, he/she might ask about the risk of exposure for Q-fever. Upon hearing that I had a high risk exposure a few days earlier, Q-fever would be considered right away and appropriate measures could be taken.
Also, as strange as it sounds, in my utopian world physicians would ask about pet health. Yes, it may seem strange if your doctor were to ask "So how are you doing today? And how's your dog been feeling lately?" - but it might be important. Illness in your pet may be associated with illness in you or other members of your household. Knowing that a pet is sick might give some indication of that (a) certain disease(s) are more likely in a person. Also, if the sick pet has been to a veterinarian for testing, those results might be useful to the physician. There's no guarantee that a pet and owner that are sick have the same thing, but a general principle of medicine is that a single cause is more likely than co-incidental independent problems.
For example:
Similar to the case of psittacosis in a pet store employee that I reported about recently, let's say that you own a bird and it's been sick for a week or so. It's weak and not eating well. You then come down with a fever and cough - something that's not uncommon. However, when your astute physician asks about the health of your pets, he/she gets concerned about the fact that your bird is sick. Your doctor contacts your bird's veterinarian, and it becomes clear that the bird could be infected with Chlamydophila psittaci, the cause of psittacosis in people. Your doctor therefore puts psittacosis on top of the list of potential problems, and instead of telling you to go home and rest, he/she takes some blood samples to try to diagnose it the infection and may even start treatment right away. Because your physician identified a higher risk situation with your sick bird, you get prompt treatment, you start to feel better in 24 hours and it's unlikely you'll have any major problems. (The mortality rate from psittacosis is < 1% in people that are treated properly. If the diagnosis is missed, the mortality rate increases to 20%, and you also run the risk of complications such as heart valve damage.)
Lambing season and Q fever
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I have a small flock of Soay sheep and lambing season started today (too early, but better than the -30C weather from a few days ago). For someone like me, lambing season inevitably triggers thoughts about Q fever, a zoonotic disease that is most commonly associated with contact with small ruminants like sheep and goats (especially sheep). The disease is caused by the bacterium Coxiella burnetii. This organism is highly infectious - very few bacteria are required to cause infection - and is considered a potential bioterrorism agent. Coxiella burnetii can be transmitted by direct contact with an infected animal, or by inhalation of organisms in dust or dirt that get blown into the air. It can be carried by healthy animals several species, but the greatest risk of transmission is from sheep and goats around the time of birthing (lambing and kidding, respectively). At that time, large numbers of C. burnetii can be shed with the placenta and fetal fluids, and can also be found on the newborn animals. Close contact with the animal and these tissues during lambing, such as with our first lambing this morning - a stillborn lamb that was stuck at the shoulders and required some manipulation to free it - can result in transmission of C. burnetii.
On a happier note, the second lambing in our flock was unassisted, although I still handled the little guy to make sure he was okay.
Q fever can affect people of any age or health status. Disease can range from mild to life-threatening. More information on Q fever can be found on the websites of the Ontario Ministry of Health and Long-Term Care and the Centers for Disease Control and Prevention (CDC), as well as the previous Worms & Germs post entitled "Q Fever - From Goats to People (and Pets!)". The disease can cause miscarriage in pregnant women. People with heart valve disease or vascular grafts are also at high risk for serious disease from this infection.
- It is prudent to consider all sheep and goats Q fever-positive unless proven otherwise (which is difficult to do).
- Contact with newborn lambs and kids, placentae and fetal fluids of sheep and goats, and any area contaminated by these tissues should be avoided as much as possible. If contact is necessary, it should be done by low-risk people, and careful attention should be paid to hygiene, especially handwashing.
- Pregnant sheep and goats should not be used in petting zoos. Unfortunately, this is actually a common occurence.
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- Live birthing exhibits, where sheep or goats give birth in public during fairs or similar events, should not be held. If they are held, they should be in an area where there is no direct or indirect contact with the public, unlike this picture (right).
- While we focus on sheep and goats, many different species can shed Coxiella burnetii, including cattle and cats. It is reasonable to consider all animals a risk around the time of giving birth, and ensure that hygiene practices are optimal.
- At my place, Q fever control consists mainly of careful attention to hygiene around newborn lambs and their ewes, and not allowing my kids to handle newborn lambs.
- Like most zoonotic diseases, hand hygiene is a critical infection control measure.
Q Fever - From goats to people (and pets!)
Q fever is an infection caused by the proteobacterial organism Coxiella burnetii. Although usually not very common, C. burnetii can be carried by sheep, goats, and cattle, as well as birds and even sometimes cats and dogs. Animals often show no signs of illness, although the infection sometimes causes miscarriage, particularly in sheep and goats. Coxiella burnetii is also transmissible to humans. People are much more susceptible than animals to disease from Q fever. Even so, only about 50% of individuals that become infected show signs of illness, which can range from flu-like symptoms to pneumonia and hepatitis (liver infection). About 1-2% of infections in people are fatal.
Infected animals shed C. burnetii in their stool, urine and milk, but the highest number of organisms are shed in birth fluids and placentae. Coxiella is able to survive very well in hot, dry soil, and when dust and dirt from contaminated areas are stirred up into the air, the organism can be inhaled. This is the most common means of transmission, although direct contact with an infected animal or its stool or urine can also transmit the disease. Transmission from drinking milk from an infected animal is very rare, but is more likely if the milk has not been pasteurized. Cats and dogs can be infected by and transmit C. burnetii in all the same ways (especially through birth fluids), but they very rarely get sick. Ticks can also transmit the disease.
Q fever is one of the most infectious diseases in the world. As little as one C. burnetii organism is enough to infect a susceptible person. There are a few things to keep in mind to help reduce the risk of being exposed to this pathogen:
- Only eat/drink pasteurized dairy products.
- The main risk from cats and dogs (especially cats) is when they give birth. If you have a cat or dog that has kittens/puppies, wear gloves if you have to touch the babies or any placentae. Afterwards, cleaning the area very thoroughly to physically remove any tissue or fluid residue is very important, because most disinfectants cannot kill C. burnetii. Always wash your hands thoroughly after handing newborn kittens or puppies.
- On dry, windy days, avoid farms or areas where sheep or goats are kept.
- Avoid sheep and goat farms during the lambing/kidding season.
