Zika Virus in Dogs and Cats

Zika virus was first discovered in Africa back in the 1940’s in a monkey with a mild fever. Since then, the disease has spread all over the world. In humans, the virus causes a birth defect called microcephaly which means ‘small brain’. In animals, the virus has  been found primarily  in non-human primates. Most exposed monkeys and apes show no signs of illness. A small number will develop a mild, short-lived fever.  The virus tends to appear in monkeys and apes that live close to humans who have the virus. A recent study of Brazil’s monkeys identified the virus in a small number of monkeys. So far, no monkey or ape babies have been born with microcephaly from Zika. It is unclear at this time whether the monkeys and apes are getting the virus from humans or vice versa. The prevalence of the virus in non-human primates is also unknown.

Other than the non-human primates, there  is no evidence of Zika virus infections causing disease in other animals. One study from Indonesia performed in the 1970’s found that the virus could infect livestock and bats but there are no documented cases of any of these animals transmitting  Zika virus to humans. More research is needed to determine if Zika is a zoonotic disease meaning animals can infect people (examples are rabies, ringworm and leptospirosis) or a reverse zoonotic disease meaning people infect  (example is MRSA ).

Like dengue fever, yellow fever and West Nile virus, Zika virus is transmitted  by mosquitos of the Andes species. Female mosquitos need the protein contained in blood to lay eggs. When mosquitos bite, they inject saliva into the wound that contains an anticoagulant to keep the victim’s blood from clotting. Their saliva can contain all kinds of infectious agents including viruses, bacteria and parasites (heartworm disease, malaria, etc.) contracted from prior victims. Once infected, a single mosquito can transmit disease to many animals and/or people.  When monkeys and apes are infected with Zika, they develop antibodies against the virus in approximately 14 days. The antibodies clear the virus out of the blood stream stopping the spread of the disease. Since monkeys and apes are quarantined in screened in facilities for 31 days when entering the United States, this should prevent the disease spreading into local mosquitos. Currently, it is unknown if monkeys and apes are reservoirs for the disease.

The bottom line is that Zika virus is not a threat to dogs and cats. There are no studies that show canines or felines can be infected with the virus or spread it to humans.


-‘Questions and Answers: Zika Virus and Animals’, ARIZONA VETERINARY NEWS, Aril 2016.

-‘Zika and Animals: What we know.’ CENTERS FOR DISEASE CONTROL AND PREVENTION, Update June 8, 2016.

Heat Exhaustion in Dogs and Cats

Heat exhaustion is a life-threatening condition that occurs in animals of all kinds. It is also called heat stress, heat stroke and hyperpyrexia. In the clinic, I see it most often in dogs. When dogs and cats are not able to dissipate heat, their body temperature soars well above the normal range of 100 to 102.5 degrees Fahrenheit. If the body temperature rises over 105.5, the internal organs are injured.  Kidney failure, liver disease, clotting problems, bloody diarrhea, vomiting, gastric ulceration, seizures and coma are a few of the conditions that may occur. Even with aggressive treatment, the prognosis is poor.

In my experience, heat stroke occurs most often when animals with problems cooling themselves are exposed to excessive heat and/or humidity. Here is a list of the health factors associated with heat exhaustion:

  1. Obesity
  2. Brachiocephalic breeds (The short and broad head is often associated with narrowed nostrils, elongated soft pallets and narrowed windpipes making it difficult to breathe.)  – In dogs this includes bulldogs of all varieties, Shih Tzu, Lhasa apsos, Boxers, Pugs and Pekinese. In cats, Persians and Himalayans are brachiocephalic. Some of these breeds like boxers and mastiffs are also heavily muscled which compounds the problem.
  3. Laryngeal paralysis
  4. Heavy coated breeds – Long hair cats especially Maine coon cats, Siberian huskies, Samoyeds,  Malamutes, etc

Environmental factors also play a huge role in causing heat exhaustion. Every summer, I am saddened to hear of children and pets who died after being left in a car. In climates with extreme temperatures including Las Vegas and Phoenix, leaving a pet outside can kill them. Recently, the evening news reported the death of a Labrador retriever who was left on an apartment balcony. I have seen animals develop heat stroke from the blowers used after grooming. High humidity is also lethal because panting isn’t as effective.

If you live with a pet prone to heat stroke, please keep them out of the heat.  I have seen heat stroke develop in as little as five minutes in geriatric pets who went outside and then couldn’t get back in the doggy door.  Watch for rapid respirations, a depressed attitude and dark red gums.  They may also experience vomiting and diarrhea.  If the dog is not cooled off quickly, their condition rapidly deteriorates into bloody vomiting, collapse, bloody diarrhea, seizures and problems breathing.  When the gum color changes into a sick, pale gray I know death is coming.

To prevent heat stroke, keep your pet at a healthy weight.  Take walks and play ball early in the morning when temperatures are mild.  Limit their time outdoors during the heat of the day to a quick trip to urinate and/or defecate in the shade.  Then, return to air conditioning.  Last, watch their tongues closely for a change in color.  If their normal pink color deepens to purple or lilac, it is time to get indoors.  I know we all like to have our pets with us to soccer and baseball games, but sometimes the safest and most loving thing to do is leave them home.  They can help you celebrate after the event!



Shell, L. “Heat Prostration”, Associate Database – VIN, last updated 8/11/2007.