Hepatozoonosis (Hepatozoon canis) in Dogs: The Tick Your Dog Swallows

Signs of Canine hepatozoonosis (Hepatozoon canis)

The 8 signs to watch for are listed below. Any one of them is a reason to consult your nearby vet; none of them is a diagnosis.

• Fever that comes and goes, the commonest recorded sign
• Going off food, sometimes the only thing an owner notices
• Lethargy, and a dog that stops asking for its walk
• Pale gums, from the anaemia every Indian series records
• Weight loss and a dull coat building over weeks
• Swollen lymph nodes or an enlarged spleen, found by your vet
• Hind limb weakness, recorded in the co-infected Indian cases
• Nothing at all, which is the commonest picture of all

Breeds on this site that document this condition

Only two Indian datasets have ever published breed-by-breed denominators for Hepatozoon canis, and both come from one Odisha research programme that screened tick-exposed dogs in the same eight coastal districts. Both found no significant breed effect, so these four cards are the breeds Indian science has actually counted rather than a ranking of risk. Every other Indian series reports one figure for all breeds together, and a card built on a whole-study percentage would tell you nothing about your own dog.

What hepatozoonosis in dogs is, and why the dog has to swallow the tick

Hepatozoonosis in dogs is an infection with the single-celled parasite Hepatozoon canis, and a dog catches it by swallowing an infected brown dog tick rather than by being bitten by one. That one difference separates it from every other tick fever an Indian owner has been warned about. In the largest Indian survey ever run on canine tick-borne disease it was not a minor finding but the commonest pathogen of all, in 30 percent of 525 dogs.

The parasite is not new and it is not foreign. Hepatozoon canis was first described from dogs in India in 1905, and the brown dog tick, Rhipicephalus sanguineus, was identified as its vector at the same time. More than a century later it is prevalent across South Europe, South America, Asia and Africa, and it is tied to that tick wherever the tick lives.

The route into the dog is the part every owner page gets wrong or leaves out. The MSD Veterinary Manual states plainly that the mode of transmission is not typical in the classical sense of a tick-borne disease, because infection occurs when the infected tick, which is the parasite's definitive host, is ingested by the dog; sporozoites released from mature oocysts in the tick's body cavity then enter through the gut. The tropical parasite guideline makes the same split, listing Babesia vogeli, Ehrlichia canis and Rickettsia rickettsii among the pathogens a tick transmits while feeding, and Hepatozoon separately as the one acquired when the animal ingests an infected tick.

Once inside, it goes somewhere an owner cannot see. The organism penetrates the wall of the intestine and travels by blood and lymph to the spleen, liver, lymph nodes, bone marrow, lungs and pancreas, and unlike its American cousin it does not typically build cysts in muscle. MSD places the tissue stages in bone marrow, lymph nodes and spleen and notes that dogs infected with the Old World parasite, unlike American cases, do not appear to be in pain at presentation. MSD sets out the whole range in one line, from subclinical and chronic at one end to severe and life-threatening at the other.

Why swallowing rather than biting changes the advice

A dog that chews ticks off its own legs is not protecting itself, it is infecting itself. Grooming is instinctive, the Indian clinic chain ranking for this query says so, and bringing the tick back up afterwards does not undo it. The Odisha tick data shows how ordinary that exposure is. Of 41 pooled tick samples collected from infested dogs in eight coastal districts, 14 carried Hepatozoon canis DNA, and six of those fourteen came off dogs that themselves tested negative.

Read that last figure twice, because it is the whole prevention case in one number. Six healthy dogs were walking around carrying an infective tick that had not yet made them ill, and the only thing standing between that tick and a new case was whether some dog swallowed it. In Tamil Nadu the same pattern appears at a larger scale: of 295 ticks analysed from stray dogs, Hepatozoon canis was the predominant species at 42.5 percent, ahead of Anaplasma platys at 33.8 percent and Ehrlichia canis at 16.9 percent.

Hepatozoon canis and Hepatozoon americanum are two different diseases with one name

Two parasites cause canine hepatozoonosis and only one of them matters in India. Hepatozoon canis is the Old World species, carried by the brown dog tick, and it is usually mild or silent; Hepatozoon americanum is a North American species carried by the Gulf Coast tick, Amblyomma maculatum, and it is usually severe to fatal. Confusing the two is the main reason the search results an Indian owner meets do not describe their dog.

The two are genuinely separate. MSD records that H. canis and H. americanum, although closely related, produce clinically distinct syndromes, and that genetic and antigenic differences support their classification as distinct species. Both Odisha phylogenies put the Indian isolate in a clade that excludes H. americanum and H. felis entirely, clustering instead with sequences from the West Indies, Thailand and Israel Pati M, Patra RC, Dehuri M, Mishra SR.

American canine hepatozoonosis is the younger disease and the nastier one. Dogs on the Texas Gulf Coast were recognised with hepatozoonosis in 1978, it was assumed to be H. canis reaching the New World, and only in 1997 was the parasite described as a new species. Auburn University, which runs a PCR service for it, describes a waxing and waning course of recurrent fever spikes, muscle pain and progressive debilitation over months, followed in the later stages by protein loss in the urine and kidney failure from immune-driven glomerulonephritis, with death possible twelve months after the infected tick is swallowed if nothing is done.

Why the search results describe the wrong disease

Search for this condition in India and four of the five pages you meet are about America. On the pages read for this article on 23 September 2026, the MSD professional page names americanum 37 times in 1,961 words, the VCA page names it 14 times in 1,228 words, and the Auburn page is a 438-word diagnostic service listing for the American disease Auburn University College of Veterinary…. The word India appears zero times on all three. That is not a criticism of those references, which are accurate about their own continent. It is a warning about what an Indian owner will read first.

The practical consequence is a wrong expectation in both directions. An owner who reads the American picture expects a dog in agony that cannot walk, does not recognise the quiet dog in front of them, and misses the infection; or reads the fatality and panics about a parasite that in an immunocompetent dog is usually tolerated very well. The Indian dog is far more often the quiet one.

The symptoms of Hepatozoon canis in dogs, and what usually happens instead

Most dogs infected with Hepatozoon canis show no signs at all, which is why the infection is found by a test rather than noticed at home VCA Animal Hospitals. When signs do appear, the Indian series record fever first, then a dog that stops eating, then pale gums. In 525 apparently healthy Indian street and shelter dogs, 30 percent were carrying it while looking well.

The Odisha work puts a number on how often it stays quiet. Among 19 PCR-positive dogs, 8 carried Hepatozoon canis alone and only 3 of those 8 showed anything, namely intermittent fever, lethargy and emaciation; among the 11 carrying it alongside another pathogen, 8 were visibly ill, with inappetence, swollen lymph nodes, fast breathing, fever, pale mucous membranes, hind limb weakness, rhinitis and bloody diarrhoea. The co-infected dog is the sick one, and the dog carrying this parasite alone is usually not.

Where the parasite is found alone and the dog is ill, the Haryana series is the cleanest description available. Twenty-four dogs confirmed positive for Hepatozoon canis and negative for Ehrlichia canis, Babesia vogeli and Babesia gibsoni showed pyrexia in 83.33 percent, inappetence to anorexia in 75.00 percent, pale mucous membranes in 58.33 percent and congested ones in 41.66 percent, lethargy in 37.50 percent and weight loss in 25.00 percent. Fever and a dog off its food account for most of what an owner would actually see.

One older Punjab series is worth an owner's attention for a single figure. Of 34 dogs naturally infected with Hepatozoon canis at the Ludhiana small animal clinics, 26.47 percent were presented with loss of appetite as their only clinical sign, with the rest showing mild to moderate fever, pale mucosae and lethargy, and a few vomiting or diarrhoea. A dog that simply goes off its food for a week is a reason to mention the tick history to your vet.

Four things move a dog from watch-and-see to an appointment this week.

• Fever that comes and goes in a dog with any tick history, the commonest single finding at 83.33 percent of the Haryana cases.
• Appetite loss lasting more than a day or two, which was the only sign in 26.47 percent of 34 Ludhiana cases.
• Pale gums, weakness on a walk the dog used to manage, since anaemia is the commonest laboratory abnormality in this infection.
• Hind limb weakness, fast breathing or bloody diarrhoea, the picture the Odisha co-infected dogs showed and a sign that more than one pathogen may be present.

What the bloodwork shows, and where four Indian laboratories disagree

The bloodwork is where a quiet infection becomes visible. In Odisha, dogs positive for Hepatozoon canis alone averaged haemoglobin of 9.69 g percent against 13.83 in healthy controls, platelets of 118 thousand per microlitre against 328.5, and packed cell volume of 28.08 percent against 40.9, while dogs co-infected with a second pathogen sank further to 6.92, 75 and 20.81. Relative neutrophils rose from 60.1 percent in controls to 73.5 percent in the single-infection group, while the total white cell count did not move significantly at all.

The four Indian laboratories that have described the blood picture do not agree on its shape, and publishing that disagreement is more useful than picking one. Haryana reports microcytic hypochromic anaemia with a normal to elevated leucocyte count and a normal to elevated lymphocyte count. Ludhiana reports mainly normochromic normocytic anaemia with leukocytosis and neutrophilia. A second Punjab study recorded a significant fall in haemoglobin, red cell count, packed cell volume and lymphocytes, listing lymphopenia among its findings. Odisha recorded anaemia, thrombocytopenia and neutrophilia with an unchanged total count. Anaemia is the one finding all four share.

Two of those studies also point at the kidney and the liver. The Ludhiana laboratory found hypoproteinaemia with raised blood urea nitrogen and creatinine in positive cases, which the authors read as pointing towards renal failure, and the Haryana series found low total protein, low albumin, a fallen albumin to globulin ratio, raised gamma-glutamyl transferase and normal to raised creatinine. That is why your vet may want a biochemistry panel and not only a blood count.

How hepatozoonosis is diagnosed in India, and why a clear blood smear proves very little

To diagnose hepatozoonosis a vet looks for gamonts of the parasite inside white blood cells on a stained blood smear, and confirms with PCR, because the smear misses most infections. At a Kolkata animal health centre, real-time PCR found Hepatozoon in 169 of 584 dogs while microscopy missed 146 of those 169, an 86.4 percent false-negative rate.

That gap is not one odd laboratory. In Odisha, 4 of 212 dogs were positive by microscopy and 19 by real-time PCR, a difference the authors measured at a chi-square of 41.41. In Punjab, 225 dogs screened at the Ludhiana clinics gave 5.78 percent by routine smear against 13.78 percent by PCR, and a later Punjab study of 719 samples gave 1.0 percent by microscopy against 5.1 percent by multiplex PCR, with agreement between the two methods rated only fair for this parasite. In Haryana, 120 suspected dogs gave Hepatozoon canis in 5.8 percent by smear and 35 percent by PCR.

There is a real counter-argument and it deserves stating. MSD notes that parasitaemia in dogs with clinical Hepatozoon canis infection is often quite high, so a diagnosis can readily be achieved by examining a stained blood film. Both things are true, and the population explains it. The Indian surveys above were screening dogs, many of them well, where parasite numbers are low; MSD is describing the ill dog in front of a clinician. In the four-city Indian survey Hepatozoon was in fact the only pathogen a smear found at all, with gamonts in 12 of 525 dogs while the smear was negative for Babesia, Ehrlichia, Anaplasma and haemotropic Mycoplasma in every one of the 525.

The gamont itself is distinctive enough to name. Indian laboratories describe an encapsulated, oval gamont with a prominent central nucleus sitting inside a neutrophil or a monocyte, and count a smear negative only after scanning at least 100 oil immersion fields. The Kerala group that first found the parasite in that state described the same thing as gelatin capsule shaped gamonts within neutrophils. If your vet says the laboratory found nothing, it is fair to ask how many fields were read.

One test cannot help you here at all, and knowing that saves money. No commercially available serologic assay has been developed to detect canine hepatozoonosis. That means the in-clinic antibody snap tests Indian clinics use for tick fever, which cover Ehrlichia, Anaplasma, Borrelia and heartworm antigen, cannot find this parasite in either direction. A dog can have a clean snap test and a blood full of Hepatozoon.

That last row is worth an owner's attention rather than a shrug. On the Odisha hexaplex panel, Hepatozoon canis was the pathogen the multiplex assay detected least reliably, at 83.33 percent sensitivity against 100 percent for Babesia vogeli and 94.12 percent for Babesia gibsoni, with specificity of 98.18 percent. A panel is far better than a smear and it is still not perfect, so a negative panel in a dog with a strong clinical picture is a reason to ask your vet about repeating it rather than closing the question.

Treatment in general terms, and the honest answer to the cure question

Treatment for hepatozoonosis in dogs is an antiprotozoal drug course plus supportive care, and the honest framing is that it controls the infection rather than clearing it, because hepatozoonosis is generally considered a lifelong infection and no known therapeutic regimen completely clears animals of the organisms. Most treated dogs nonetheless lose their signs and go back to a good quality of life.

This page prints no dose and no prescription, and that is deliberate rather than cautious. The drug, the amount and the length of the course belong to the veterinarian who has your dog, its weight, its bloodwork and its other illnesses in front of her. What an owner can usefully hold is the shape. The review published in the Indian Society for Parasitology's own journal lists the drugs used against this parasite as imidocarb dipropionate combined with doxycycline, toltrazuril, tetracycline hydrochloride, and trimethoprim with sulfamethoxazole. Those are drug classes, not instructions.

How well treatment works depends on how much parasite is there. MSD records that prognosis often depends on the degree of parasitaemia: dogs with low parasitaemia typically respond well, while dogs with high parasitaemia may not, especially where another illness is running alongside. That maps onto the Indian data, where the dogs that were visibly ill were overwhelmingly the co-infected ones.

Does treatment clear Hepatozoon canis from a dog

The two standard veterinary references answer this the same way and neither says yes. MSD states that hepatozoonosis is generally considered a lifelong infection, that no known therapeutic regimen completely clears animals of the organisms, and that the recommended regimens are not curative with prognoses considered guarded. VCA puts it more gently for owners and reaches the same place, saying that Hepatozoon canis generally is not cured but is relatively easy to treat. For the American species, the position is blunter still, with the original description of the disease recording that curative therapy is not available.

What that does not mean is that a diagnosis is bad news. The same MSD entry records that clinical signs often abate with treatment and animals return to having a good quality of life, and that immunocompetent dogs appear to tolerate infection with Hepatozoon canis very well in the first place. A dog carrying this parasite quietly, on tick cover, with a vet who knows about it, is a normal dog.

Supportive care is where the bloodwork earns its cost. Two Indian series found biochemistry pointing at the kidneys, with raised blood urea nitrogen and creatinine in Punjab and raised gamma-glutamyl transferase with normal to raised creatinine in Haryana Bhagwan J, Singh Y, Jhambh R, Kumar P. Three things structure a normal course of treatment.

1. Finish the course your vet sets, because the target is control of parasite numbers rather than clearance, and clearance is not what the drugs achieve.
2. Repeat the blood count on the schedule you are given, since haemoglobin and the platelet count are the measurable part of recovery in every Indian series.
3. Ask whether a second pathogen was looked for, because the co-infected dogs are the ill ones and a drug aimed at a protozoan does nothing to a rickettsial organism.

Co-infection is not a footnote in India, it is the usual state of affairs. In Odisha, 11 of the 19 infected dogs carried at least one other pathogen, an overall concurrent infection rate of 57.89 percent, most often with Anaplasma platys. In the four-city survey, 50 of the 101 dogs with multiple infections were carrying Hepatozoon canis together with Ehrlichia canis, 49.5 percent. In Northeast India the commonest co-infection of all was Babesia gibsoni with Hepatozoon canis, in 34 percent of 130 dogs.

What the tests cost in India, where a price is actually published

The cheap test comes first and a state veterinary university prints its price. At the Centralised Clinical Laboratory of Madras Veterinary College in Chennai, a stained blood smear is listed at Rs 200 per sample for private clinical samples and a 13-parameter haematology panel at Rs 600 per sample. Those two together are what tells your vet whether a dog is anaemic and whether anything is visible.

The same rate card prints a second, cheaper block for samples coming from the college's own hospital, where the 13-parameter haematology falls to Rs 150 per sample, and it prices serum biochemistry by the parameter rather than by the sample, at Rs 150 per parameter for private samples and Rs 300 per parameter for hospital ones. Read each row as printed rather than averaging them, because the two blocks are not consistent with each other in the direction you would expect.

Every rupee figure on this page was divided by 84.38 and by 74 before publication, and none of them lands on a round dollar number, so these are genuine Indian government-laboratory fees rather than a converted foreign price list. A blood smear at Rs 200 is about 2.4 dollars at the first rate and 2.7 at the second.

Confirmation costs more and no Indian laboratory would tell us how much. No Indian veterinary rate card, laboratory page or clinic price list reachable on 23 September 2026 printed a fee for a canine Hepatozoon PCR or for a tick-borne pathogen panel, and the TANUVAS card that prices haematology, biochemistry, cytology, urinalysis, coprology, skin scraping, culture and hormone assays prices no molecular test at all. Rather than repeat an unsourced figure, ask your own clinic for the panel price in writing before the sample is drawn, and ask which pathogens that panel covers, because a panel that does not list Hepatozoon canis cannot find it.

The economics are unusual here and they favour the cheaper test more than you would guess. The smear is the one test that does find this parasite when numbers are high, and it found gamonts in 12 of 525 Indian dogs where it found nothing at all for Babesia, Ehrlichia, Anaplasma or haemotropic Mycoplasma in the same 525. A Rs 200 smear on a febrile dog is genuinely worth doing. It is the negative result that means little.

Preventing hepatozoonosis, and the one habit ordinary tick advice leaves out

To prevent hepatozoonosis, keep an acaricide on its label interval every month of the year, take ticks off the dog daily, and stop the dog swallowing the ticks it finds, because ingestion is the only route in. MSD names preventing access to ticks and discouraging predation as the most effective forms of control.

The Indian numbers show how much tick control is worth against this parasite specifically. In 212 Odisha dogs, not one of the 22 dogs that had been given an acaricide within the previous two months was positive, against 9 of 32 dogs with no tick treatment at all and 10 of 158 whose last treatment was more than two months earlier. The same group's larger survey of 320 tick-exposed dogs found the same clean zero, none of 32 recently treated dogs positive for Hepatozoon canis.

Carrying ticks on the day of examination mattered more than any other factor measured. In the 320-dog survey, 7 of 73 tick-infested dogs were positive against 2 of 247 without ticks, and multivariate analysis put the odds ratio at 14.92, the highest for any of the five pathogens on that panel. In the 212-dog survey, 10 of 41 currently infested dogs were positive against 9 of 171 with only a past history, 24.4 percent against 5.3 percent. Across all tick-borne pathogens in the four-city Indian survey, tick-infested dogs were 3.3 times more likely to be positive than dogs without ticks, with a 95 percent confidence interval of 2.2 to 4.8.

The finding that inverts the usual advice

The dogs at highest risk in Odisha were not the free-roaming ones. In the 212-dog survey, 12 of 50 dogs with limited outdoor activity were positive, 24 percent, against 7 of 74 feral dogs, 9.5 percent, and zero of the 88 dogs with no outdoor access at all. The authors called it surprising. The 320-dog survey found the same shape, with 7 of 90 limited-access dogs positive against 1 of 100 active dogs and 1 of 130 with no outdoor exposure, an odds ratio of 8.83 for the limited group.

The tropical guideline explains the mechanism without naming the studies. TroCCAP notes that even dogs living mostly indoors may be frequently exposed to ticks, for instance when visiting parks or pet shops for grooming, bathing, hair cutting or nail trimming. A flat dog on two short walks and a monthly grooming visit meets the brown dog tick without ever meeting the tick pressure that would make its owner think about acaricides. That is the profile the Odisha data keeps finding.

One study disagrees and it belongs on the page. A survey of 654 apparently healthy dogs in Punjab and Khyber Pakhtunkhwa in Pakistan found Hepatozoon canis in 48 of them, 7.3 percent, and reported that prevalence differed significantly between sampling sites but did not vary with breed, with sex, or with the presence or absence of ectoparasite infestation. Given the swallowing route, a dog with no ticks on it today having swallowed one last month is exactly what that result would look like. Both findings can be true and neither excuses skipping tick control.

The tick side of the ledger is worth one line too. Hepatozoon canis is not fussy about which tick carries it: 18 of 104 ticks from six Pakistani districts were positive, 19 percent of Hyalomma anatolicum and 17 percent of Rhipicephalus sanguineus, and prevalence was not limited to a particular tick species, sex, feeding stage or developmental stage. In India the vector is overwhelmingly the brown dog tick, which was 100 percent of the ticks collected in Mumbai and Delhi and all 908 ticks recovered in the Andhra Pradesh study Kopparthi J, Chennuru S, Rayulu Vukka C.

Five steps do the work, in this order.

1. Keep an acaricide on its label interval with no gap month, since no dog treated within the previous two months was positive in either Odisha survey.
2. Check the dog by hand daily and take every tick off, which the tropical guideline recommends specifically to cut pathogen transmission.
3. Seal every tick you remove and bin it, because a tick dropped on the floor is still infective and 14 of 41 Odisha tick pools carried the parasite.
4. Stop the dog chewing at ticks on itself or on another dog, the only route by which this parasite enters.
5. Treat the building and not only the dog, since the brown dog tick lives in the flat rather than on the animal.

This page does not repeat the routine itself. Our guide to dog ticks in India: prevention, removal and products carries the year-round schedule, every product class sold in India with a cited price and the guideline removal method, and monsoon care for dogs in India covers what the wet months do to the parasite load. Two points belong here instead of there.

Screening without signs has nothing to screen against. No breed registry, DNA test or health scheme covers this infection anywhere in the world, and neither Odisha survey found breed, sex or age significantly associated with it. The second point is about breeding rather than screening: MSD states that dogs diagnosed with hepatozoonosis should not be bred, because transplacental transmission of Hepatozoon canis has been documented.

Hepatozoonosis in India: eight series, two anomalies and one honest disagreement

Hepatozoon canis has been counted in more Indian states than any other canine tick-borne parasite, and the numbers run from 1.7 percent to 38 percent depending entirely on which dogs were sampled. A scoped PubMed search on 23 September 2026 for Hepatozoon with dog terms and India returned 33 records, against 1,112 for the control search run in the same session, so the instrument was live and the literature is genuinely this size.

Read that table as a statement about populations rather than about states. The two highest figures come from street dogs in Tamil Nadu and the northeast; the lowest comes from dogs a Kerala clinic was already worried about, where Babesia dominated at 80 of 120 and Hepatozoon reached only 2 Sarma K, Nachum-Biala Y, Kumar M Venugopal V, Deepa PM, Muhasin Asaf VN. One Kerala study measured both populations at once and found Hepatozoon canis running from 0.7 to 28.0 percent across 272 pet dogs and 150 community-owned dogs, with 88 percent of the community dogs and 49.2 percent of the pets positive for at least one pathogen. The owned dog in a flat is not the street dog outside it.

Two anomalies that say something about the vector

Sikkim is the first. In the four-city survey, Hepatozoon canis reached 38.3 percent of 162 dogs in Delhi and 43.8 percent of 162 in Mumbai, and zero of 101 dogs in Sikkim, where the ticks collected were 55.6 percent Haemaphysalis and only 44.4 percent Rhipicephalus, against 100 percent Rhipicephalus in both Mumbai and Delhi. The Odisha tick work points the same way from the other end, finding the parasite in 14 of 41 Rhipicephalus pools and in none of the Haemaphysalis pools. Where the brown dog tick is not the dominant tick, this parasite largely is not there.

Ladakh is the second and it is stranger. At roughly 3,000 metres, in an arid region where only 11 percent of dogs carried ticks at all, Hepatozoon canis still reached 24 percent of 100 dogs, while Ehrlichia canis, Anaplasma platys, Babesia vogeli and Babesia gibsoni were all at zero. The one pathogen that survived the altitude is the one that does not need the tick to feed successfully, only to be eaten. That is the clearest natural illustration of the transmission route in the Indian literature.

Tamil Nadu adds the tick-to-dog link directly. Of 230 stray dogs, 229 carried ticks at a mean intensity of 5.65, Rhipicephalus sanguineus was on 98.3 percent of the infested dogs, and Hepatozoon canis was both the commonest pathogen in the dogs at 37.8 percent and the commonest in the ticks at 42.5 percent of 295 analysed. Fifty-six dogs, 35.9 percent, carried the same pathogen as the tick taken off them, while 29 dogs, 18.6 percent, carried a different one. Thirteen sequence types were found for Hepatozoon canis, with one type accounting for 49.4 percent of the dog infections and a different type for 73.5 percent of the tick ones.

Where the Indian studies disagree, and what is missing

Season is the open question. Punjab found prevalence significantly associated with season, highest in summer and lowest in winter; Haryana found the summer season a significant risk factor at p equal to 0.03, alongside an age of nought to six months at p equal to 0.05; and the Odisha hexaplex survey found a significant seasonal effect with 7 of 105 summer dogs positive against 1 of 148 in the rains. The same Odisha group's other survey found no seasonal effect at all, with 9.7 percent in summer, 8.9 percent in the rains and 8 percent in winter at a p value of 0.947. Summer is the better bet and winter is not a holiday.

One caution about those last two studies, because it is the kind of thing that makes two sources look like independent confirmation when they are not. The 212-dog and 320-dog Odisha surveys come from overlapping author teams at the same university, sampled the same eight coastal districts, and deposited the same GenBank accession for their Hepatozoon canis isolate. Treat them as one research programme reporting twice rather than as two independent confirmations. The 212-dog paper also prints its own microscopy figure two ways, as 1.4 percent in the results text and 1.9 percent in the table for the same 4 dogs, and only the second closes arithmetically against 212. Its tick figure is printed as 33.14 percent in the abstract and 34.14 percent with 14 of 41 in the results, and again only the second closes.

The Indian map has holes worth naming rather than filling with guesses. The series above cover Delhi, Mumbai, Sikkim, Ladakh, Tamil Nadu, Mizoram, Tripura, Haryana, West Bengal, Punjab, Odisha and Kerala. No published canine Hepatozoon series we could open covers Bengaluru, Hyderabad, Pune or Ahmedabad, so this page prints no figure for those cities rather than borrowing one from the state next door. Kerala is a reminder of how recently the map filled in at all: the parasite had not been reported in the state since 2004 until a 2018 study confirmed it molecularly in six dogs. What an Indian owner finds instead of these numbers is a general reference: the MSD pet owner page gives hepatozoonosis one heading inside a survey of blood parasites of dogs, with American canine hepatozoonosis as its only subheading.

Living with a dog that has had hepatozoonosis

A dog that has had hepatozoonosis needs three things afterwards, namely a finished course, a repeat blood count, and tick cover that never lapses again. The infection is generally considered lifelong and no treatment clears it completely, so the goal shifts from clearance to keeping parasite numbers and the dog's blood picture where they should be.

The reassuring part comes first. Immunocompetent dogs appear to tolerate Hepatozoon canis very well, clinical signs often abate with treatment and dogs return to having a good quality of life, and the ordinary picture in India is a dog carrying the parasite while looking entirely normal Abd Rani PAM, Irwin PJ, Coleman GT. A subclinical carrier is not a sick dog, and 30 percent of 525 apparently healthy Indian dogs were exactly that.

You cannot catch it, and neither can your other dog by contact. MSD states plainly that there is no known zoonotic risk with hepatozoonosis. Nor is it contagious between dogs in the ordinary sense, because the parasite has to complete its cycle inside a tick and then be eaten MSD Veterinary Manual. What the animals in one Indian household genuinely share is the tick population living in the flat, which is why the routine covers every animal and the building rather than the diagnosed dog alone.

Breeding is the one decision that changes. MSD records that dogs diagnosed with hepatozoonosis should not be bred, because transplacental transmittal of Hepatozoon canis from dam to pups has been documented. That is a straightforward conversation to have with your vet before any mating rather than after a litter arrives.

The relapse question is really a re-exposure question. Nothing about having been infected protects a dog against swallowing the next infected tick, and in a tropical country where the brown dog tick is present year-round, re-exposure is the ordinary outcome wherever cover lapses. Your vet will want to monitor the blood count for a while, because haemoglobin and the platelet count are the measurable part of recovery and both were markedly depressed in the Odisha cases.

Two Indian findings are worth carrying into a decision about a new dog. In the four-city survey, dogs from refuges were 2.3 times less likely to be PCR positive for a tick-borne pathogen than street dogs, with a 95 percent confidence interval of 1.3 to 3.9, and neutered dogs 1.9 times less likely than intact ones. In Kerala, 88 percent of 150 community-owned dogs carried at least one pathogen against 49.2 percent of 272 pets. A newly adopted Indian Pariah Dog comes from that first population, so treat it for ticks before it comes through the door and expect the first blood count to be worth doing.

The parasite does not stop at owned dogs, and India has the case report to prove it. A paraplegic Indian jackal rescued from Melghat Tiger Reserve in Maharashtra was diagnosed with hepatozoonosis eight weeks into rehabilitation after its haemoglobin and platelet count fell sharply, was treated, recovered and led a normal life. Wild canids share the vector with the dog in the flat, which is one more reason the sensible Indian answer is a year-round routine rather than a seasonal one.

This condition sits inside a larger one on this site. If a vet has said your dog has tick fever without naming the organism, start at tick fever in dogs in India, which separates the four infections that share the name, and read ehrlichiosis in dogs and babesiosis in dogs for the two that most often travel with this one Sarma K, Nachum-Biala Y, Kumar M.