Tick fever isn't one disease. It is the name used for a group of infections that ticks pass to dogs, and a survey of 525 street and shelter dogs across four Indian climate zones found six of them. The commonest signs are fever, lethargy, poor appetite, and weight loss, and none of those points at a tick-borne cause on its own. That's why the diagnosis matters more than the symptom list.
What tick fever covers
Two infections sit behind most of the term. Ehrlichiosis is caused by Ehrlichia canis, and its formal name, tropical canine pancytopenia, tells you where in the world it does its damage. Babesiosis is caused by a Babesia species, and in India that increasingly means one species in particular.
Six pathogens turned up by PCR in the 2011 Parasites and Vectors survey, and they are not evenly spread. Two of them account for most of what a vet sees: Hepatozoon canis at 30 percent of the 525 dogs and Ehrlichia canis at 20.6 percent. Behind those sit Mycoplasma haemocanis, Anaplasma platys, and the two Babesia species, the rarer of which, Babesia gibsoni, turned up in a single dog in that sample and matters far more than its 0.2 percent suggests.
Those dogs were 77 percent strays and 23 percent shelter animals, with no owned pets in the sample, so treat the percentages as a picture of street and shelter dogs in Sikkim, Ladakh, Delhi, and Mumbai rather than a figure for your own dog.
Hepatozoon canis is the odd one out. A dog doesn't catch it from a bite. It catches it by swallowing an infected tick, usually while chewing at itself.
What the Indian data shows
Two findings from Indian research change how this disease should be thought about here.
One is that a single diagnosis is often incomplete. Nearly 39 percent of the infected dogs in the 2011 survey carried more than one pathogen, and among those with multiple infections, about half had Hepatozoon canis and Ehrlichia canis together. The authors wrote that Indian vets should be aware that finding one pathogen raises the possibility of several, which may need different clinical management. A dog that partly responds to treatment aimed at one organism may be carrying another.
The other concerns which Babesia species is winning. A study of 330 working dogs from organised kennels across seven Indian states, from West Bengal and Nagaland to Jammu and Kashmir, Uttar Pradesh, and Maharashtra, published in Preventive Veterinary Medicine in 2019, sequenced its positive samples and found Babesia gibsoni in 47 cases against Babesia vogeli in four. The authors described a positive selection of the smaller form over the larger one in this country and called it a serious concern, because the prognosis with Babesia gibsoni is considered poor compared with Babesia vogeli.
Those 330 dogs were animals already suspected of babesiosis, not a random sample, so the study says which species dominates among diagnosed cases rather than how common the disease is.
The signs, and why they mislead
The Companion Animal Parasite Council lists the common presentation as fever, lethargy, low mood, poor appetite, and weight loss. Swollen lymph nodes show up sometimes. Where platelets have dropped, you may see pinpoint bleeding under the skin, larger bruising, or nosebleeds. Eye involvement including uveitis and retinal detachment has been reported.
Babesiosis in its uncomplicated form is driven by the destruction of red blood cells, so the Indian working dog study lists fever, loss of appetite, pale gums, anaemia, fast breathing, fast heart rate, an enlarged spleen, jaundice, and general apathy.
The complicated form is much worse. That study's third group of cases presented with epilepsy, jaundice, kidney failure, and in one Labrador, septic shock with disseminated intravascular coagulopathy, which was fatal.
Nothing on those lists is specific to tick fever, and that's the trap. It sends people home reassured.
The diagnosis problem
The standard first test in most Indian clinics is a stained blood smear read under a microscope. It is cheap, fast, and available everywhere. It is also insensitive, and the Parasites and Vectors survey, the Preventive Veterinary Medicine study, and the Companion Animal Parasite Council (CAPC) all say so.
In the 2011 survey, smear microscopy was negative for Babesia, Ehrlichia, Anaplasma, and Mycoplasma in every single one of the 525 samples. PCR on the same blood found 261 infected dogs.
In the 2019 working dog study, the same 330 samples returned 5.15 percent positive by microscopy, 9.09 percent by simple PCR, and 15.45 percent by nested PCR. The authors recommended nested PCR as the screening assay and reported that simple PCR results were statistically significantly false negative.
CAPC states that Ehrlichia and Anaplasma organisms are usually rare on blood smears and can be found only during acute infection, and therefore recommends other diagnostic methods.
The 2011 authors are careful about this and so should we be. Blood smear examination remains the simplest and most accessible test a vet has, and it's reasonably sensitive during acute, clinically significant infection. The problem isn't that the smear is useless. The problem is that a negative smear rules out much less than most pet parents believe it does.
What to ask your vet for
CAPC's guidance is to diagnose ehrlichiosis and anaplasmosis on a combination of four things: clinical signs, serology, PCR testing, and haematology with a platelet count.
The platelet count is the one to ask about by name. CAPC links the pinpoint bleeding and nosebleeds seen in these infections to thrombocytopenia, which is a low platelet count, and it names haematology with a platelet count as one of the four things a diagnosis should rest on.
If your dog has had ticks in the past few months and is off colour, ask whether the workup includes a platelet count and whether PCR is available. Both are reasonable questions and a good vet won't mind them.
Treatment, and why some dogs relapse
Treatment depends on the organism, which is the reason identifying it matters.
The Indian working dog study reported something uncomfortable about Babesia gibsoni specifically. Clearing the parasite completely with commonly prescribed anti-protozoal drugs was not achieved, and clinical relapses were often observed. The authors called it a significant therapeutic challenge and a diagnostic one.
So a dog that improves and then slides back some weeks later hasn't necessarily been treated badly. With this particular parasite, that pattern is documented in the Indian literature.
A dog can carry this and look completely fine
Of the 51 dogs confirmed positive in the 2019 study, a third were classified as apparently healthy with subclinical babesiosis. Within that group of 17, microscopy caught 4, simple PCR caught 8, and nested PCR caught all 17.
CAPC says the same thing about the other family of organisms: subclinical infections with Ehrlichia and Anaplasma species are common among dogs.
A healthy-looking dog with a history of ticks can be carrying something. That is an argument for getting prevention right, given what the same study says about how treatment goes. Which products are actually approved in India is covered in dog tick medicine in India.
Frequently asked questions
How long after a tick bite does tick fever show up?
No Indian study establishing an incubation period for tick fever turned up in targeted searching for this article. What is documented is the other end of the timeline: the Companion Animal Parasite Council states that Ehrlichia can be transmitted within three to six hours of a tick attaching, which is why removing ticks quickly is worth doing properly.
Does one sick dog put the others in the house at risk?
Through the ticks, yes it does. CAPC describes Ehrlichia canis as cycling between domestic dogs and the brown dog tick, and notes that ticks, males particularly, can transfer between pets living together. So the thing to deal with is the tick population in the house, which is covered in ticks on dogs in India. Whether these particular organisms infect people was not researched for this article and no claim is made about it either way.
Is there a vaccine for tick fever in dogs?
No vaccine against any of these tick-borne infections turned up in the sources used for this article. Prevention means keeping ticks off the dog month after month, which is different work from the vaccinations your vet gives on a schedule.
Can tick fever come back after treatment?
With Babesia gibsoni, yes, and it is documented. The 2019 Indian working dog study reported that complete clearance with commonly prescribed anti-protozoal drugs was not achieved and that relapses were often seen.
My dog's blood smear was negative. Should I stop worrying?
That alone is not enough. A smear found nothing in all 525 samples of the 2011 survey while PCR found 261 infected dogs, and CAPC notes these organisms are usually visible on a smear only during acute infection. If your dog has signs and a tick history, ask about a platelet count and PCR.
Sources
- Abd Rani et al. A survey of canine tick-borne diseases in India. Parasites and Vectors, 2011;4:141. Open access: https://link.springer.com/article/10.1186/1756-3305-4-141 (PubMed record: https://pubmed.ncbi.nlm.nih.gov/21771313/)
- Mittal M, Kundu K, Chakravarti S, Mohapatra JK, Singh VK, Raja Kumar B, Thakur V, Churamani CP, Kumar A. Canine babesiosis among working dogs of organised kennels in India. Preventive Veterinary Medicine, 2019;169:104696. Free full text: https://pmc.ncbi.nlm.nih.gov/articles/PMC7126866/ (PubMed record: https://pubmed.ncbi.nlm.nih.gov/31311632/)
- Companion Animal Parasite Council. Ehrlichia spp. and Anaplasma spp. (dog), guideline last updated 1 June 2015: https://capcvet.org/guidelines/ehrlichia-spp-and-anaplasma-spp/
- Companion Animal Parasite Council. Ticks (dog), guideline last updated 30 March 2023: https://capcvet.org/guidelines/ticks/
