The Danger from Cats: Cat Scratch Fever or Disease and Toxoplasmosis Jeannine Miesle, M.A., M. Ed. February, 2018
We see, over and over, adults allowing babies, young children, birds, and other pets to interact with kittens and cats. I have been told to mind my own business, that the cat is very gentle and sweet, and they are, of course, supervising. But no one can be quick enough to stop a cat when it strikes. No one can get there in time to prevent a scratch, bite, or lick. Most people won't listen; they think it won't happen to them, their child, or their bird.
Bartonellosis or Cat Scratch Disease in humans
Some think cats present no threat to their birds' or children's health. "Cat-Scratch Fever" is caused by a Gram-negative bacteria known as Bartonella henselae. It is spread through cat scratches and bites; the saliva penetrates the broken skin or mucosal areas such as the nose, mouth, and eyes. Licking by the cat will also transmit this disease. The wound is a puncture wound and it inoculates the bacteria into the skin, and because of the feathers, the owner doesn't see it, then a few days later the bird is dead.
This is not something to be taken lightly. Cats use this toxic bacteria to kill in the wild; the instinct to attack, scratch, bite and claw are built into them. I encourage anyone with a cat to keep it away from the children, birds, and other pets. Adults also can get this disease, so they need to be careful as well.
Children will develop hyperplasic nodes in the lymph systems of both the underarm and groin areas which require surgery for biopsy and a lengthy treatment and medication program. fever, headache, fatigue, muscle soreness and poor appetite are other signs. Most people recover in just a few weeks. In about 5-15% of cases, other more serious conditions may develop, including heart, eye, brain, intestinal, and skin problems.
The symptoms include:
- Blisters or papules at the site of the scratch/bite
- Fever, headache
- Hyperplasic or swollen lymph nodes, particularly in the armpits and groin
- Malaise
- An enlarged spleen
The diagnosis is often difficult to attain unless the parent is aware of the cat scratch/bite. A biopsy is required to establish a definitive diagnosis. Antibiotics such as Azithromycin are required to destroy the bacteria. Some pathogens are resistant to antibiotics, and this is becoming a serious problem.
Toxoplasmosis
There has been some question about the incidence and potential for toxoplasmosis infection in birds, particularly in pet birds. For the most part, the possibility of pet birds kept in an indoor, hygienic, safe environment is low; however, there are some ways in which even these birds might contract the disease if cats are a part of the household. Many people now keep chickens and other poultry, and these birds are at risk of contracting Toxoplasmosis gonii infection as well.
Symptoms
Toxoplasmosis is a zoonotic (can be transmitted from animals to humans), parasitic, protozoan disease. It is more common in aviaries and backyard poultry than commercial producers. It is characterized by disorders of the central nervous system, but it can also affect reproductive, musculoskeletal and visceral organs (internal organs of the chest and abdomen). Clinical signs include:
- Weight loss and inappetence
- Shrunken comb (in poultry)
- Drop in egg production, whitish diarrhea
- Incoordination and trembling
- Opisthotonos (severe spasm in which the back arches; head is back and tail is up)
- Torticollis (twisting of the neck or Star-gazing)
- Blindness. All chickens infected before eight weeks of age develop clinical signs. In older birds, infection can be asymptomatic (infected hosts show no symptoms) or latent (symptoms only develop under certain conditions).
What causes toxoplasmosis?
Toxoplasmosis is caused by the parasitic protozoa, Toxoplasma gondii. Cats are the only definitive hosts, and so both wild and domestic cats serve as the main reservoir of infection. There are three infectious stages in the lifecycle of this protozoa.
- Stage one occurs when the parasite is within the tissue of the host,
- Stage two occurs when the protozoan is excreted by the host in the feces and
- Stage three occurs when the protozoan is transferred across the placenta in mammals to their offspring.
Transmission can therefore occur by eating infected tissue, contact with infective feces, or transfer from an infected mother to a developing fetus (in mammals only). When cats use their litter boxes, they carry the parasite on their feet and other parts of their body. It is then transferred to the human or bird.
T. Gondii infection in humans
"Toxoplasma gondii (T. gondii) is a single-celled parasitic organism that can infect most animals and birds. Because it reproduces only in cats, wild and domestic felines are the parasite's ultimate host.
When a person becomes infected with T. gondii, the parasite forms cysts that can affect almost any part of the body — often your brain and muscles, including the heart. If you're generally healthy, your immune system keeps the parasites in check. They remain in your body in an inactive state, providing you with lifelong immunity so that you can't become infected with the parasite again. But if your resistance is weakened by illness or certain medications, the infection can be reactivated, leading to serious complications. Women who are pregnant should have another person handle all cat droppings.
Although you can't "catch" toxoplasmosis from an infected child or adult, you can become infected if you come into contact with cat feces that contain the parasite. You may accidentally ingest the parasites if you touch your mouth after gardening, cleaning a litter box or touching anything that has come in contact with infected cat feces. Cats who hunt or who are fed raw meat are most likely to harbor T. gondii."
Toxoplasmosis transmission
"The only known definitive hosts for Toxoplasma gondii are domestic cats and their relatives. Unsporulated oocysts (eggs) are shed in the cat’s feces . Although oocysts are usually only shed for 1-2 weeks, large numbers may be shed. Oocysts take 1-5 days to sporulate in the environment and become infective. Intermediate hosts in nature (including birds and rodents) become infected after ingesting soil, water or plant material contaminated with oocysts Oocysts transform into tachyzoites, the next cellular stage, shortly after ingestion. These tachyzoites localize in neural and muscle tissue and develop into tissue cyst bradyzoites, which reproduce inside host cells to form tissue cysts in the new host. Cats become infected after consuming intermediate hosts harboring tissue cysts. Cats may also become infected directly by ingestion of sporulated oocysts. Animals bred for human consumption and wild game may also become infected with tissue cysts after ingestion of sporulated oocysts in the environment.
While it is true that pet birds which are kept in an indoor, clean environment have little risk of contracting toxoplasmosis, birds which are kept outdoors have a greater risk of contracting it since other animals and birds may have access to the outdoor aviary, and their droppings may fall into the aviary and contact the birds directly or be consumed by the birds. Indoor pet birds are at risk if they have access to the cat droppings (if the cat does not use the little box at all times), or the humans fail to clean exposed skin after handling the cat feces, such as after cleaning the litter box. The oocysts have a long life cycle and may infect multiple intermediate hosts. Cats which are allowed to roam outside may kill and eat wild birds or other animals which harbor the disease. They may become clinically ill or be carriers. When allowed inside they may then infect humans, birds, or other animals through direct or indirect contact with feces.
Geographic Distribution
Serologic prevalence data indicate that toxoplasmosis is one of the most common human infections throughout the world. A high prevalence of infection in France has been related to a preference for eating raw or undercooked meat, while a high prevalence in Central America has been related to the frequency of stray cats in a climate favoring survival of oocysts and soil exposure."
Avian susceptibility to T. Gondii
T. gondii has very little specificity for intermediate hosts and is a zoonotic disease. All avian species should be considered susceptible intermediate hosts; those that ingest other intermediate hosts or cat feces are at greater risk, and pigeons and canaries are most likely to present with clinical disease. Management focuses on eliminating T. gondii from collections by removing cats and cat feces from the environment.
References:
1. CDC.gov. Toxoplasmosis. http://www.cdc.gov/dpdx/toxoplasmosis/index.html
2. Peteducation.com. Toxoplasmosis. http://www.peteducation.com/article.cfm?c=1+2134&aid=3305
3. The Mayo Clinic. Toxoplasmosis. http://www.mayoclinic.org/diseases-conditions/toxoplasmosis/basics/causes/CON-20025859
4. The Poultry Hub. Toxoplasmosis. http://www.poultryhub.org/health/disease/types-of-disease/toxoplasmosis/
5. Welleban J. Coccidial Diseases of Birds. In: Current Therapy in Avian Medicine and Surgery. Ed: Brian Speer, DVM. Elsevier Pub. 2015.
6. Wikipedia: Toxoplasmosis gondii. https://en.wikipedia.org/wiki/Toxoplasma_gondii#Tachyzoites
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