Engorged tick attached behind a cat's ear — blood parasites and tick-borne disease in cats in India

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Blood Parasites in Cats: Hemotropic Mycoplasma, Babesiosis, and Surra

Jun 10 • 10 min read

The flea you removed from your cat last week was not just an irritant. It was a potential courier. Tucked inside that flea or the tick after it may have been a blood parasite that is now living in your cat's red blood cells, quietly destroying them.

Blood parasites are one of the most under-discussed reasons cats become pale, lethargic, feverish, and suddenly anaemic. In India, where fleas and ticks are active year-round, they matter more than most cat owners realise.

Key Takeaways

Blood parasites in cats are tiny organisms bacteria or protozoa that live inside or on the surface of red blood cells, causing haemolytic anaemia and sometimes death if untreated.
The most clinically important blood parasite in Indian cats is Mycoplasma haemofelis a bacterium spread by fleas, ticks, and bite wounds that destroys red blood cells through an immune-mediated mechanism.
Cats can carry Mycoplasma haemofelis silently for months as healthy carriers. Disease flares when the cat is immunocompromised by FeLV, FIV, stress, or another illness.
Babesiosis in cats is an emerging concern in India the Merck Veterinary Manual specifically names India alongside South Africa as areas of increasing reports.
Surra (Trypanosoma evansi) is endemic across Asia including India, spread by biting flies, and cats can act as silent reservoirs spreading the parasite to other animals even when showing minimal symptoms themselves.
Year-round flea and tick prevention is the single most effective intervention against all three of India's most relevant feline blood parasites. Not seasonal year-round.

What Are Blood Parasites in Cats?

Diagram of three types of blood parasites in cats — Mycoplasma haemofelis Babesia felis and Trypanosoma evansi Surra

Blood parasites are microscopic organisms either bacteria or protozoa that live inside the bloodstream and specifically target red blood cells. According to the Merck Veterinary Manual's Diseases Caused by Blood Parasites in Cats, these organisms are often spread by ticks or biting insects. Some can also be transmitted to humans.

The damage they do is not passive. These parasites attach to, invade, or damage red blood cells triggering the immune system to destroy those cells as "foreign." The result is haemolytic anaemia: red blood cells being consumed faster than the bone marrow can replace them. This is not slow, gradual depletion. In severe cases, it is a crisis that can kill a cat within days.

What makes blood parasites clinically dangerous is their combination of properties:

They cause severe disease while remaining difficult to detect on routine blood tests
Many cats carry them silently for months before disease breaks out
They are spread by vectors (fleas, ticks, biting flies) that are active year-round across India
Cats with FeLV, FIV, or other immune-compromising conditions are at dramatically higher risk of severe disease

Four categories of blood parasites affect cats, per the Merck Veterinary Manual: Cytauxzoonosis, Hemotropic Mycoplasmosis, Hepatozoonosis, and African Tsetse-Transmitted Trypanosomiasis. Plus two additional conditions with dedicated Merck pages: Babesiosis and Surra. Of these, the three most clinically relevant to Indian cat owners are Hemotropic Mycoplasmosis, Babesiosis, and Surra.

Hemotropic Mycoplasmosis — The Most Important One in India

Hemotropic mycoplasmosis is caused by hemotropic mycoplasmas also called hemoplasmas which are tiny bacteria that attach to and infect the surface of red blood cells. The Merck Veterinary Manual describes them as bacteria that are attracted to, infect, and damage red blood cells causing haemolytic anaemia.

These bacteria are now classified in the genus Mycoplasma the same genus that causes respiratory and genital infections in many species. But the hemoplasmas are a distinct group. They have no cell wall (which means antibiotics like penicillin that target cell walls do not work against them), they cannot be grown in culture outside the body, and they attach directly to red blood cell surfaces in characteristic shapes rods, rings, cocci visible under a microscope.

The Merck Veterinary Manual's professional section on Hemotropic Mycoplasma Infections explains the mechanism: hemoplasmas attach to the surface of the host's red blood cells and, under certain conditions, penetrate the cell. The host's immune system then targets those infected cells for destruction. The haemolysis is therefore immune-mediated the parasite is the trigger, but the cat's own immune system is doing the actual destroying.

Three Species, Different Severity

Three hemoplasmas infect cats. They are not equally dangerous.

1. Mycoplasma haemofelis formerly called Haemobartonella felis. This is the most pathogenic of the three. The Merck Veterinary Manual states that M. haemofelis can cause serious anaemia even in healthy cats. It is the primary cause of what was historically called "feline infectious anaemia" (FIA).

2. Candidatus Mycoplasma haemominutum a smaller organism that typically causes subclinical infection in healthy cats. It may become clinically relevant in immunocompromised cats and is one of the most commonly detected hemoplasmas worldwide.

3. Candidatus Mycoplasma turicensis the least studied of the three; associated with mild to moderate anaemia, primarily in immunocompromised cats.

Mixed infections (a cat carrying more than one species simultaneously) occur and can produce more severe disease than single-species infection.

How Mycoplasma haemofelis Spreads in India

The Merck Veterinary Manual's professional section outlines transmission routes:

Arthropod vectors fleas, ticks, flies, and mosquitoes. The Merck Veterinary Manual's primary cat-owner page specifically names fleas and other blood-sucking insects as the route most commonly cited. In India's year-round warm climate, flea populations never fully die down between seasons. Every month of the year is flea month in most of India. This means the transmission window for M. haemofelis never closes.

Bite wounds direct transmission, possibly associated with fighting between cats, is suspected and supported by the Merck Veterinary Manual's professional section which notes that hemoplasma DNA has been found in saliva, on the gingiva (gums), and on the claw beds of infected cats. A cat that gets into a fight with a stray that carries M. haemofelis can become infected without any flea involvement.

Blood transfusion if a donor cat carries hemoplasmas and is not screened, the recipient receives infected red blood cells directly. This is why PCR testing of donor cats before transfusion is mandatory in responsible veterinary practice.

Vertical transmission from queen to kittens. The Merck Veterinary Manual's professional section confirms vertical transmission has been reported in cats. Kittens born to infected queens can carry hemoplasmas from birth.

Silent Carriers: The Dormant Threat

This is the aspect of hemotropic mycoplasmosis that most owners and many vets underestimate.

The Merck Veterinary Manual states it explicitly: healthy adult cats infected by hemoplasmas might not show any symptoms. Severe disease can occur in cats infected by FeLV, FIV, or other disease-causing agents.

A cat can carry M. haemofelis in its blood for months or even years without any visible signs. The immune system keeps it in check. But then something weakens the immune system a FeLV infection, FIV progression, another illness, prolonged corticosteroid treatment, stress and the hemoplasma multiplies unchecked. The immune system now attacks both the parasite and the red blood cells it has colonised. The cat crashes into haemolytic anaemia that can progress to a crisis within days.

This is why testing for hemoplasmas should be part of the workup for any unexplained anaemia in a cat, particularly cats with outdoor access, cats from multi-cat households, or cats with known FeLV/FIV status. The cat may have been carrying the parasite for a long time before the illness appeared.

Signs of Hemotropic Mycoplasmosis

Cat gums comparison — healthy pink gums vs pale jaundiced gums from blood parasite haemolytic anaemia

The Merck Veterinary Manual lists the symptoms:

Fever often the first sign; may be intermittent early in the course
Pale or yellow (jaundiced) mucous membranes pale gums from anaemia; yellow gums from bilirubin released by destroyed red blood cells
Poor appetite cats stop eating as the illness progresses
Weakness and depression the cat becomes increasingly lethargic and unresponsive
Enlarged spleen the spleen enlarges as it works to clear damaged red blood cells from circulation
Weight loss and extreme thinness in chronic cases
Breathing difficulty in severe anaemia, when oxygen delivery is critically reduced

The Merck Veterinary Manual adds a critical outcome statistic: up to one-third of untreated cats with severe infection might die. This is not a wait-and-see illness.

Oxygen therapy and blood transfusions may also be required in addition to antibiotics for severe cases.

If your cat has fever as part of this picture, our guide on how to prevent fever in your cat covers what fever signals and when it warrants emergency action.

Diagnosis: Why the Blood Smear Often Misses It

Diagnosis is confirmed via blood tests, but not by the standard smear alone.

Hemoplasmas can be seen under microscopy as small dark bodies on the surface of red blood cells rods, rings, or cocci. In acute infection with heavy parasitaemia, this can be diagnostic. But:

The organisms fall off red blood cells quickly after blood collection
They are present intermittently — a smear taken on the right day might show them; a smear taken a day later might not
The smaller species (Ca. M. haemominutum) are particularly difficult to distinguish from staining artefacts

The Merck Veterinary Manual's professional section confirms: PCR (polymerase chain reaction) assays have greatly enhanced diagnosis of hemoplasmas. PCR can detect small amounts of hemoplasma DNA in blood even between parasitaemia peaks. It can also distinguish between the three feline species important because M. haemofelis requires more aggressive treatment than the smaller species.

In India, PCR for hemoplasmas is increasingly available at veterinary diagnostic laboratories in major cities. If your cat has unexplained regenerative haemolytic anaemia and the blood smear is negative, push for PCR testing before concluding hemoplasma disease is absent.

Treatment: Doxycycline and Supportive Care

The Merck Veterinary Manual states that the disease is treated with antibiotics and supportive care. Oxygen and blood transfusions might also be required.

The primary antibiotic is doxycycline a tetracycline class antibiotic that is effective against M. haemofelis and the related species. The Merck Veterinary Manual's professional section confirms doxycycline and the related oxytetracycline as the mainstay of treatment for acute hemoplasma infections. Pradofloxacin and marbofloxacin have also shown efficacy against M. haemofelis.

Important practical note for Indian cat owners: doxycycline in cats must be given with food or followed with water to prevent oesophageal injury. Cats that receive doxycycline tablets without adequate water can develop oesophageal strictures a serious complication. Always give with food or use the liquid formulation if available.

Corticosteroids are sometimes added to reduce immune-mediated red blood cell destruction since the anaemia is partly driven by the cat's own immune attack on parasitised cells. The Merck Veterinary Manual's professional section notes that glucocorticoids may be useful to decrease erythrophagocytosis in cases of severe haemolysis.

The Merck Veterinary Manual adds an important caution for transfusion: some animals may require blood transfusion, but animals must be carefully monitored because the parasite can rapidly infect transfused cells as well. This is why the transfusion in a hemoplasma case is a bridge to antibiotic treatment, not a standalone fix.

Critical limitation: treatment eliminates clinical signs but may not eliminate the infection. The Merck Veterinary Manual's professional section notes that treated animals may remain carriers and may experience periodic clinical relapses, especially when stressed or immunosuppressed. Cats that have had hemotropic mycoplasmosis should be considered lifelong potential carriers.

Babesiosis — An Emerging India-Relevant Threat

Babesiosis is a tick-borne disease caused by Babesia protozoa that infect and destroy red blood cells. The Merck Veterinary Manual's Babesiosis in Cats lists the species that can infect cats: Babesia felis, Babesia cati, Babesia leo, and Babesia vulpes.

Here is the India-specific statement from the Merck Veterinary Manual, quoted directly in paraphrase: babesiosis in cats is currently of greatest veterinary concern in South Africa, but reports are increasing in parts of Africa and India. Cases remain rare in Europe and elsewhere.

This makes babesiosis an emerging priority for Indian veterinarians and cat owners not yet the crisis it is in South Africa, but a condition whose Indian incidence is rising and whose presentation will increasingly appear in Indian veterinary practices.

Babesia parasites work differently from hemoplasmas. They are protozoa (more complex single-celled organisms) that actually invade the interior of red blood cells. Once inside, they multiply and rupture the cell when they exit causing direct red cell destruction rather than immune-mediated destruction.

Signs, Diagnosis, and Treatment of Feline Babesiosis

The Merck Veterinary Manual lists the common symptoms of babesiosis in cats:

Fever
Weakness
Pale gums (anaemia)
Jaundice yellowing of skin, eyes, or gums
Red or dark urine haemoglobin released by destroyed red blood cells passing through the kidneys (haemoglobinuria)
Weight loss
In severe cases: sudden collapse or death

The Merck Veterinary Manual notes that some animals develop long-term infection with progressive anaemia. Acute cases range from mild illness to life-threatening disease. The symptom overlap with hemotropic mycoplasmosis is significant which is why laboratory testing is essential to confirm the diagnosis.

Diagnosis: because these symptoms resemble several other diseases, laboratory testing is required. A blood smear may show intraerythrocytic parasites (pear-shaped or ring-shaped organisms within red blood cells) in active infection. PCR is more sensitive and species-specific.

Treatment: the Merck Veterinary Manual states that treatment can include prescription medications to kill the parasite and supportive care such as anti-inflammatory drugs, antioxidants, and corticosteroids. Blood transfusions can be lifesaving in severely anaemic animals.

The specific antiparasitic drugs used are prescription medications requiring veterinary diagnosis and authorisation. Supportive care while the antiparasitic drugs work is as important as the drugs themselves.

Prevention the Merck Veterinary Manual is clear: keeping ticks off your pet is critical. Use veterinarian-recommended tick control products. Check pets regularly for ticks and remove them promptly and safely.

The Merck Veterinary Manual also notes that human babesiosis is rare the species infecting cats and dogs are generally different from those that infect people. Most human infections are from different Babesia species via tick bites or contaminated blood transfusions. Immunocompromised people are at higher risk.

Surra — The Biting-Fly Parasite Your Vet May Not Test For

Surra is a disease caused by Trypanosoma evansi a protozoan parasite that moves through the bloodstream. The Merck Veterinary Manual's Surra in Cats states it occurs in North Africa, the Middle East, Asia, and the Far East — putting India squarely within its geographic range.

What makes Surra different from the other blood parasites covered here is its vector: it is not tick-dependent. Unlike Babesia or M. haemofelis, T. evansi does not need ticks to spread. It is carried from animal to animal by biting flies horse flies and other blood-feeding flies. Because biting flies are widespread across Asia and not limited to tick habitats, Surra has spread across a far wider geographic range than tick-borne diseases.

The Merck Veterinary Manual is important in calibrating cat owner concern about Surra: cats usually have mild disease. In other species horses, camels, dogs Surra can be severe or fatal. In cats, the disease tends to be subclinical or mild.

However, the Merck Veterinary Manual adds a critical point: infected cats can help spread the parasite to other species. A cat that carries T. evansi and is bitten by a horse fly can infect that fly, which then carries the parasite to horses, cattle, or dogs in the same compound or village. In India, where cats often live in or near working-animal households, this reservoir role is clinically and economically significant.

The Merck Veterinary Manual notes that many animals show no clear symptoms but still carry the parasite. Cats may carry T. evansi for months without obvious illness. When symptoms do appear, they include weight loss, anaemia, weakness, and lethargy the same non-specific signs that overlap with most other blood parasites.

Diagnosis is confirmed by finding parasites in blood either on a smear or by PCR. Treatment uses antiparasitic drugs prescribed by a veterinarian. The Merck Veterinary Manual does not indicate Surra poses major human health risk.

Cytauxzoonosis and Hepatozoonosis — Context for Completeness

The Merck Veterinary Manual covers two additional blood parasite diseases. A brief note on their relevance to India:

Cytauxzoonosis (Cytauxzoon felis) the Merck Veterinary Manual describes this as life-threatening, spread by ticks from bobcats to domestic cats in the southeastern United States. It is not a significant concern in India, where the natural reservoir (bobcat) does not exist. Worth knowing the name not a priority for Indian cat management.

Hepatozoonosis (Hepatozoon felis) often causes no clear symptoms in cats. Found globally, including Asia. The Merck Veterinary Manual notes it is diagnosed by finding the parasite in blood or via specialised lab tests, and that tick prevention is recommended since related parasites in other species are tick-borne. Not a primary clinical concern in Indian cats currently, but tick control addresses it as part of broad parasite management.

The Common Thread: Tick and Flea Control as Prevention

If there is one action this entire guide points toward, it is this: year-round, consistent, veterinarian-recommended tick and flea control for every cat.

The Merck Veterinary Manual's blood parasites section states prevention for hemotropic mycoplasmosis is based on good flea and insect control and monitoring for illness. The babesiosis section states keeping ticks off your pet is critical. The Surra section, for its biting-fly vector, recommends controlling flies and managing the environment in areas where the disease is common.

The overlap is complete. One consistent external parasite control programme addresses the transmission routes of all three India-relevant blood parasites simultaneously.

Why monthly, year-round not seasonal?

India does not have a flea or tick "off-season." In the tropics and subtropics, temperature and humidity levels that support flea egg development and tick questing persist year-round. Treating your cat for fleas and ticks only during monsoon season, or only in summer, leaves months of unprotected exposure during which transmission can occur.

Spot-on products the most reliable format for cats

Spot-on treatments apply to the skin at the back of the neck and distribute through the cat's coat and skin oils, providing month-long protection from the application site. They are more reliable than shampoos (which wash off) or sprays (which require even application), and more consistent in bioavailability than oral products for cats.

FRONTLINE PLUS CAT SPOT ON by Boehringer Ingelheim contains Fipronil (kills adult fleas and ticks) and S-Methoprene (an insect growth regulator that prevents flea eggs and larvae from developing). It provides one month of protection against fleas and ticks in cats over 8 weeks of age and weighing at least 1 kg. Approved for use in breeding, pregnant, and lactating queens relevant for cattery management where vertical transmission of hemoplasmas is a risk.

FIPROFORT PLUS CAT SPOT ON by Sava Vet contains the same active combination Fipronil (9.8%) + S-Methoprene (11.8%) in a veterinarian-formulated spot-on at a more accessible price point. It rapidly kills adult fleas and ticks while disrupting the flea life cycle for long-term control. Cat-specific formulation for cats over 8 weeks and above 1 kg.

For cats that need broader protection including against internal parasites like roundworms and heartworm, as well as external parasites SELAFORTE CAT SPOT ON (2.6–7.6 kg) by Sava Vet uses Selamectin (12%), a macrocyclic lactone that provides ectoparasitic and endoparasitic (both external and internal) control. It spreads through the hair coat within 24 hours, with systemic absorption providing internal parasite coverage simultaneously. Particularly relevant for outdoor or semi-outdoor cats with both parasite exposure risks.

All tick and flea treatments require a veterinary prescription. Discuss which product is best for your cat's weight, lifestyle, and risk profile at your next veterinary visit.

Additional prevention measures:

Check your cat for ticks after any outdoor time, particularly around the head, neck, ears, and between the toes
Keep cats indoors or supervised outdoors in tick-endemic areas during peak tick season (pre- and post-monsoon)
In multi-cat households, treat all cats simultaneously one untreated cat can re-infest others
Treat the environment too: flea larvae develop in carpets, soft furnishings, and cat bedding. Environmental sprays or regular hot washing of bedding break the cycle

For cats that scratch excessively because of flea activity which can accelerate transmission of hemoplasmas through flea faeces entering scratch wounds our guide on how to prevent excessive scratching in cats covers the flea-itch cycle and how to break it.

FAQ

My indoor cat has never gone outside. Can she still get blood parasites?
Yes, though the risk is meaningfully lower. Fleas are hitchhikers they can enter your home on clothing, shoes, bags, or on another animal. If you have even occasional outdoor exposure yourself, or if you have a dog that goes outside, fleas can enter your home and infect your cat. M. haemofelis can also be transmitted directly between cats through bite wounds and saliva if you have a multi-cat household and one cat occasionally goes out, indoor cats can still be exposed. The risk is lower than for outdoor cats, but not zero.

My cat was treated for a blood parasite last year. Is she cured?
Antibiotic treatment for Mycoplasma haemofelis eliminates the clinical infection and the active haemolytic episode but the Merck Veterinary Manual's professional section notes that treated animals may remain carriers and can experience periodic clinical relapses when stressed or immunosuppressed. A treated cat should be considered a lifelong potential carrier. Continuing flea and tick prevention is still essential. If she becomes ill again especially with any anaemia, fever, or jaundice tell your vet about the prior diagnosis immediately.

How do I know if the blood parasite is Mycoplasma haemofelis vs babesiosis? Do the signs look different?
The clinical signs overlap significantly: both cause haemolytic anaemia, fever, pale or yellow gums, weakness, and weight loss. A specific distinguishing sign of babesiosis is haemoglobinuria red or dark urine caused by haemoglobin from destroyed red blood cells passing through the kidneys. This is less common with hemotropic mycoplasmosis. But the only reliable way to distinguish them is laboratory testing PCR or blood smear identifying the specific organism. Never assume which one it is based on symptoms alone.

My vet found Surra in one of my cats. Should I be worried about my other animals?
Yes, but the concern is primarily about the other animals spreading the parasite not your cats infecting your other cats directly. The Merck Veterinary Manual notes that infected cats can help spread T. evansi to other species via biting flies. If you have horses, dogs, cattle, or other animals sharing the same space as an infected cat, discuss your fly control measures with your veterinarian. The infected cat should be treated for Surra. In your other species particularly horses and dogs, who can develop severe Surra proactive testing or monitoring is appropriate.

Can I catch a blood parasite from my cat?
The short answer is: very rarely, and the risk is low for most healthy adults. The Merck Veterinary Manual notes that some hemoplasmas have been reported to infect humans. Human babesiosis is rare and is more commonly associated with different Babesia species from tick bites than from cats. Surra is very rarely reported in people. However, immunocompromised individuals those undergoing chemotherapy, on immunosuppressant drugs, or living with HIV should be aware that contact with tick-infested or parasitised animals carries a small zoonotic risk. Maintain tick control on your pets and consult your physician if you have immune concerns.

What does a tick bite on a cat look like? How do I find and remove ticks?
Ticks attach most often around the head, neck, ears (inside and behind), between the toes, and under the chin. They feel like small bumps under the fur a flat, dark brown or grey bump, ranging from sesame-seed sized (unfed) to small grape-sized (fully engorged after several days of feeding). Do not crush, burn, or pull roughly: this can force tick contents back into the wound. Use fine-tipped tweezers or a dedicated tick removal tool, grasp as close to the skin surface as possible, and pull upward with steady, even pressure. Place the tick in a sealed container. Clean the bite site with antiseptic. If you find a tick on your cat and are uncertain about the removal or your cat shows any symptoms over the following week, call your vet.