Tick-Borne Cytauxzoon Infection in Cats (Cytauxzoonosis)
- Occurrence: very rare
- Location of illness: Skin/Fur
When to visit the vet?
Urgent see a veterinarian within 24 hours
If the condition worsens / symptoms persist, consult a veterinarian.
Definition
Cytauxzoonosis is an acute, often fatal disease in cats caused by the single-celled parasite Cytauxzoon felis. This parasite attacks the red blood cells and other cells of the immune system, leading to severe health impairments.
BASICS/CAUSES:
Cytauxzoonosis is caused by the protozoan parasite Cytauxzoon felis, which belongs to the Apicomplexa group. This parasite resembles other blood-borne pathogens in many ways, such as Plasmodium, which causes malaria. Cytauxzoon felis has a complex life cycle involving both a tick host and a mammalian host.
The parasite is mainly transmitted by the American dog tick (Dermacentor variabilis) and the Lone Star tick (Amblyomma americanum). Infection occurs when an infected tick bites a cat and the parasite enters the cat’s bloodstream. Once in the blood, the parasite invades monocytes, a type of white blood cell, and multiplies there. This leads to massive cell destruction and ultimately to severe systemic disease.
The disease is particularly prevalent in the southern and southeastern regions of the United States, where these tick species are native. However, there are reports of infections in other regions, indicating a possible expansion of the ticks’ range. Cats living in wooded or rural areas are at higher risk, as these environments are favorable for ticks.
The most important facts at a glance
Cytauxzoonosis is a serious parasitic disease in cats transmitted by the bite of infected ticks, particularly of the genus Amblyomma. Outdoor cats are at higher risk as they are more frequently exposed to ticks. The disease manifests through symptoms such as fever, loss of appetite, vomiting, weakness, jaundice, and abdominal pain. In rare cases, apathy, dehydration, and convulsions can also occur. Diagnosis is based on clinical symptoms, laboratory tests, and medical history, with microscopic detection of the parasite in the blood being crucial. PCR tests can be helpful in the early stages of the disease. Therapy is challenging and combines antiparasitic drugs like atovaquone and azithromycin with supportive care to alleviate symptoms and strengthen the cat’s immune system. The prognosis is serious, with high mortality, but early and aggressive therapy can offer chances of survival. Prevention is crucial and includes the use of tick repellents and avoiding tick-infested areas. Regular checks for tick infestation are important to prevent infections. Intensive follow-up care for surviving cats is necessary as recovery can be lengthy, although some cats may develop some immunity after surviving the infection. Close cooperation with your veterinarian can provide additional prevention strategies to minimize the risk of infection.
Causes
- Transmission of the parasite through the bite of infected ticks, especially of the genus Amblyomma.
- Outdoor cats are particularly at risk due to their higher risk of tick bites.
Symptoms
Symptoms of cytauxzoonosis usually appear suddenly and develop rapidly. The most common signs include fever, lethargy, and loss of appetite. Affected cats may also show anemia, jaundice, and respiratory distress. Since the parasite affects red blood cells and blood clotting mechanisms, bleeding and poor oxygen supply to tissues can also occur.
Other symptoms can include vomiting, diarrhea, and an increased heart and respiratory rate. In severe cases, neurological symptoms such as convulsions and disorientation can occur. Without timely therapy, the cat’s condition deteriorates rapidly, often leading to death within a few days.
Diagnosis
The diagnosis of cytauxzoonosis is based on a combination of clinical symptoms, laboratory tests, and the cat’s medical history. An important diagnostic clue is the presence of ticks or a history of tick infestation.
Laboratory tests usually include a complete blood count, which can show signs of anemia and thrombocytopenia (decreased number of platelets). Definitive proof of the disease is achieved through microscopic detection of the parasite in blood smears or biopsies of affected organs. Cytological examinations can confirm the presence of schizonts, a developmental form of the parasite, in monocytes.
In some cases, molecular techniques such as polymerase chain reaction (PCR) can be used to detect the presence of Cytauxzoon DNA in the blood. These methods are particularly useful in the early stages of the disease when the parasite load in the blood is still low.
Therapy
The therapy for cytauxzoonosis is difficult and requires intensive veterinary care. Therapy usually consists of a combination of antiparasitic drugs, supportive care, and symptomatic treatment. Atovaquone and azithromycin are the most commonly used medications to treat the infection. These drugs aim to inhibit the multiplication of the parasite and reduce the burden on the cat’s immune system.
In addition to drug therapy, supportive care is essential. This includes intravenous fluids to combat dehydration, blood transfusions for severe anemia, and oxygen administration for breathing problems. Careful monitoring of vital functions and blood values is necessary during therapy to detect and treat complications early.
Antibiotics may be administered to prevent or treat secondary bacterial infections that could be favored by the cat’s weakened immune defenses. Painkillers and anti-inflammatory drugs can also be used to improve the cat’s well-being and control the inflammatory response.
Prognosis and follow-up care
The prognosis for cytauxzoonosis is serious, and the mortality rate remains high despite therapy. Without therapy, the disease almost always leads to death. With aggressive and early therapy, however, some cats can survive the infection, although the survival rate remains relatively low even under optimal conditions.
The outlook improves if the diagnosis is made early and therapy is started quickly. Cats that survive the acute phase of the disease can recover completely, but recovery can be lengthy and requires intensive follow-up care. There are reports of cats developing immunity against future infections after surviving the disease, but this protection is not complete and susceptibility can vary.
Prevention
To minimize the risk of cytauxzoonosis infection in cats, it is important to prevent contact with ticks that can transmit the parasite as much as possible. One of the most effective measures is the use of tick repellents specifically developed for cats. These products are available as spot-on treatments, collars, or sprays and should be applied regularly according to the manufacturer’s instructions.
In addition, cat owners should ensure that their animals do not roam in areas heavily infested with ticks, such as dense forests or tall meadows. Regularly checking the cat for ticks after spending time outdoors can help remove them early before they can transmit diseases.
For cats living in endemic areas or spending a lot of time outdoors, it is advisable to restrict access to such areas, especially during peak tick season. Close consultation with your veterinarian can provide additional prevention strategies tailored to the cat’s individual situation and risk. These measures can significantly reduce the risk of infection.