Incubation Period

Definition: Incubation period is a common term in medicine and may be used to describe any type of disease and pathogenic (disease-causing) organism infections. The incubation period is the time from exposure to a virus, bacteria, fungus, or parasite to the appearance of clinical signs.

It is important to note that during the incubation period, the animal may appear completely healthy with normal activity levels and no discernible symptoms. It is a good idea to isolate new pets - for their safety and for the safety of other pets - for at least a week to monitor for any signs of illness. This will allow for close monitoring of the new pet and reduce chances of infection in other pets.

Examples:

The incubation period of canine parvovirus (CPV or parvo) is 3 to 7 days. The incubation period for rabies is a few days to a few months, depending on the location of the bite wound, since the rabies virus travels up the nerves to the brain.

Lyme Disease in Cats

Lyme disease is caused by Borrelia burgdorferi, a type of bacteria that is transmitted by ticks

It is possible for cats to get Lyme disease, though it is very rarely seen in cats.

Lyme disease affects a variety of species, including humans and dogs. Lyme disease has been reported in cats after experimental infection with B. burgdorferi, though experts are still studying whether it occurs naturally in cats exposed to infected ticks. Nevertheless, it is a diagnosis to consider when cats have symptoms compatible with Lyme disease, especially in areas where Lyme disease is common.

Cats and dogs can become infected with Borrelia burgdorferi without ever developing symptoms of Lyme disease. Where Lyme disease is common, cats may test positive for exposure to the bacteria despite not showing any signs of disease.

Transmission of Lyme Disease
Ticks become infected with the bacteria by feeding on infected mice and other small animals. When an infected tick bites other animals, it can transmit the bacteria to these animals. Lyme disease is transmitted by the deer tick (blacklegged tick) and a group of other closely related ticks, the exact species varying by location. The deer tick is a small tick and may bite animals and people without being easily detected.

Cats that spend a lot of time outdoors, in areas with bush or tall grass are most at risk for being infected with Lyme disease. However, it is important to remember that ticks can be carried into yards on other animals, so even cats that don't roam far could potentially be bitten by a tick (and if you have dogs, ticks can hitch a ride into the home on the dogs). There is currently no evidence that Lyme disease is spread by direct contact between animals, including between infected pets and their owners.

Symptoms may Include

• lameness (may shift from leg to leg)
• stiffness, pain
• fever
• decreased appetite
• lethargy

Diagnosis
Because so many cats do not develop symptoms after infection with B. burgdorferi, the diagnosis of Lyme disease must be made on a combination of factors, including history (especially exposure to ticks), clinical signs, finding antibodies to B. burgdorferi bacteria, and a quick response to treatment with antibiotics. An antibody test is not enough to make a diagnosis on its own, because not all cats that are exposed to B. burgdorferi get sick, and the antibodies can persist in the blood for a long time after exposure.

Other diagnostic test such as blood tests, urine tests, x-rays, and sampling of joint fluid, may be done as well to check for more serious effects of Lyme disease such as kidney disease, and to rule out other conditions that can cause similar signs and symptoms.

Treating Lyme Disease
Treatment with antibiotics usually produces a rapid improvement in symptoms. If there are more serious issues that might be secondary to Lyme disease, such as kidney disease, a longer course of antibiotics along with additional medications is usually necessary.


Prevention of Lyme Disease
Tick control is extremely important for the prevention of Lyme disease (and other diseases that can be transmitted by ticks). Check outdoor cats daily for ticks and remove them as soon as possible, since ticks must feed for at least 12 hours (possibly 24-48 hours) before transmitting the bacteria causing Lyme disease. Be careful handling ticks, as they are potentially infective to people, too.

Products that kill ticks, such as Frontline Plus for Cats® (compare prices) can be used; be sure to follow your veterinarian's advice when using these products. Keep grass and brush trimmed in your yard, and in areas where ticks are a serious problem, you can also consider treating the yard for ticks.

Case Report: Albuterol Toxicity in a Boxer

Guest author Ahna Brutlag DVM, Assistant Director of Veterinary Services at the Pet Poison Helpline, shares this case of a common poisoning hazard for pets; human medications. In this case report, learn about Rooney the curious Boxer and the dangers of albuterol inhalers for pets.

Common causes of pet poisonings in the home
Every day, Pet Poison Helpline receives calls about pets getting into their owner’s medications. One medication that particularly concerns us is something that many of us have in our homes—albuterol inhalers.

Dogs will chew on the inhaler and, upon puncturing it, receive a very large dose of albuterol all at once. This massive dose causes toxicity by elevating the heart rate to life-threatening levels and causing very low potassium levels in the blood which, in turn, lead to extreme weakness, in-coordination, and, potentially, death. Other signs which are often seen in dogs who puncture albuterol inhalers include vomiting, dilated pupils, severe agitation/hyperactivity, elevated blood pressure and vomiting.

Case Report: Rooney the Boxer
Rooney, a 4 year old healthy male Boxer, was caught chewing on and puncturing his owner’s albuterol inhaler. Within 10 minutes he had vomited 2 times and seemed very nervous. He then began to have difficulty walking and seemed very weak. When his owners went to pick him up off the floor, they felt his heart racing. Realizing this was an emergency, they immediately rushed Rooney to his veterinarian.

Emergency vet visit
When Rooney arrived at the hospital, he was unable to walk, was panting severely, and had developed an irregular heart rhythm with a very rapid heart rate of over 240 beats per minute (normal is up to 130-150 beats per minute). The veterinarian performed blood tests and found that Rooney’s blood potassium level was below 2.0 (normal is 3.5-6.0 and any amount below 2.5 is considered life-threatening).

Albuterol toxicity management
Because of this low potassium level and high heart rate, Rooney was extremely weak and needed emergency intervention. His veterinarian immediately gave him intravenous potassium and drugs called "beta-blockers" to slow his heart rate. Within 30 minutes, Rooney had improved dramatically and was able to stand on his own. He was placed on a steady rate of intravenous potassium and given more beta-blockers over the course of the night.

Case follow up
By the next morning, Rooney was doing so well that he no loner needed extra potassium or heart medications and he was able to go home later that day.

Rooney’s case is very typical of the albuterol inhaler cases that Pet Poison Helpline is called about. Thankfully, when treated appropriately, many dogs survive albuterol poisoning. However, if left untreated, dogs may die as a result of cardiac arrhythmias and too low potassium levels.

If your pet ingests human medications
If your pet ingests a human medication always call your veterinarian immediately as other common medications such as acetaminophen (Tylenol) or ibuprofen (Advil) can also be very toxic to pets. The sooner treatment is sought for your pet, the better the prognosis.

Thank you, Dr. Brutlag, for this very timely warning and interesting case report. Thankfully a happy ending for Rooney.

H1N1 (Swine) Flu Confirmed in Iowa Cat

H1N1 (Swine) Flu Confirmed in Iowa Cat

The Iowa Department of Public Health reported that a cat became ill with H1N1 virus after 3 members of the family became ill with influenza-like symptoms on November 4, 2009. Disease specialists are unsure at this time if this is an isolated case or the start of something new.

Either way, it is important not to panic - washing hands, covering coughs, isolating sick individuals, and visiting the doctor if you are sick are your best defenses against the flu.

Alliance for Rabies Control September 2009 newsletter

The Alliance for Rabies Control's September 2009 newsletter is now available on our website at: www.rabiescontrol.net/ARCnewsletter14.pdf

It includes news about our patron Alexander McCall Smith's visit to Tanzania, rabies prevention in travelers, street dog control projects in India, a rapidly evolving virus strain in Arizona, US and updates on the next World Rabies Day to be held on 28th September, amongst other articles.

For the first time we have included hyperlinks in the pdf file. Whilst reading the pdf file you can now click on the links (highlighted by blue text) and access the linked webpages directly. We hope you find it useful.

Deborah Briggs, Executive Director of the Alliance,
and Louise Taylor, newsletter editor

Ideas

Ideas on how veterinary clinics or individual veterinarians can get involved in and support World Rabies Day:

¨ Promote the need for pets to be current on their rabies vaccines in association with World Rabies Day.

¨ Encourage your clients to vaccinate their dogs, cats, ferrets, and any valuable livestock and horses, and advise them on the required frequency of vaccination.

¨ Educate pet owners about responsible pet ownership.

¨ Promote spaying or neutering pets which may decrease undesirable behavior and will prevent them from contributing to the birth of unwanted animals.

¨ Advise clients to not leave garbage or pet food outside, as it may attract wild or stray animals.

¨ Discourage clients from bringing wild animals into their homes and keeping them as pets. This may be against state or local regulations and pose a potential rabies threat.

¨ Distribute materials in your clinics to educate your clients on rabies prevention.

When A Dog Bites

A pet bites a child, and the owner is faced with an excruciating decision: Is it safe to keep this dog?

For some, the answer is "no," and it's a decision reached more from the gut than from calm contemplation. But is that the right call to make? According to veterinarian Margaret Duxbury, not without a visit to the veterinarian.

"Given the important role dogs play in families and in critical social relationships for some people, aggressive dogs should not be euthanized unnecessarily," said Duxbury, a diplomate of the American College of Veterinary Behavior. "As caring professionals, veterinarians should take the time to establish an accurate behavioral diagnosis that allows them to evaluate the expected clinical course and specific risk factors for that problem."

Any dog may bite, given the right - or wrong - circumstances, Duxbury said.

"There are many case examples where simply improving the owner's ability to understand, read and manage their dog resolves or sufficiently reduces the problem," she said.

Duxbury says the bottom line in coming to a decision to keep the dog, turn it over to a shelter or euthanize it, is risk.

"A number of specific factors can be used to evaluate the risks posed by a particular dog in a particular household," she says.

Duxbury will share her insights into dog-bite behavior and will dissect the factors that should be taken into account if a dog bites during a program on Saturday, July 11, at the 146th AVMA Annual Convention in Seattle, Wash.

"By evaluating these factors in a standardized way with all patients, practitioners will be better able to compare the aggressive dogs they see and to advise clients in ways that promote informed and realistic decisions," Duxbury said.

Among the factors a veterinarian and a pet owner should consider are size, sex, the context in which the bite took place, bite history, warning signs, household dynamics, the prognosis for improvement and breed.

But Duxbury, like many in the field of animal behavior, warns that any consideration of breed needs to be tempered by the facts.

"Owners often want to simplify the problem they face with their own dog by looking at its breed," she said. "Breed statistics for biting dogs can be misleading because they are gathered from data on reported bites when most bites go unreported, do not include information about the overall popularity of a breed in the area and often rely on untrained witnesses for breed identification. In most cases, a well-managed, socially competent dog presents a lower risk of biting regardless of breed. ... Any dog of any breed can inflict serious or fatal injury."

That's a message that Jane Berkey, president of the Animal Farm Foundation, Inc., also wants to share. Berkey will be presenting a program on dog breed-specific legislation during the Convention on Monday, July 13.

"Veterinarians, their clients and their clients' pets in 300 cities and towns in the United States live with special burdens and added costs because of ordinances banning or restricting dogs of one or more breeds and breed mixes," Berkey said. "Thirty-six breeds of dogs and mixes of those breeds have been restricted in various combinations and groupings. These restrictions and bans compromise the human-animal bond and complicate the professional landscape for veterinarians."

Berkey will trace what she calls "demonized" dogs who have been victimized over the years by their reputation. The list includes bloodhounds, German shepherds, Doberman pinschers, Rottweilers and pit-bull type breeds. She calls it an "environment of breed discrimination."

"Focusing on breed or phenotype diverts attention from strategies veterinarians and other animal experts have consistently identified as contributing to humane and safer communities," she said. "There is so much behavioral variability within each breed, and even more within breed mixes, that we cannot reliably predict a dog's behavior or suitability based on breed alone."

Source
American Veterinary Medical Association

Feline Heartworm’s a Different Animal

Clients and veterinarians need to learn more about how it behaves in cats.

Gary D. Norsworthy, DVM

Click to Enlarge

Click to Enlarge

Severe interstitial disease can occur when immature adult heartworms die and are carried into the lungs by blood flow as seen in the lungs of this 8-year-old cat. This cat requires continual medication using corticosteroids and a bronchodilator to relieve dyspnea.

A recent study at Auburn University has shown us a new side of feline heartworms.

Dillon and Blagburn, with the financial backing of Pfizer Animal Health of New York, performed an amazing study¹. They infected three groups of cats with heartworm larvae.

The first group was untreated to see what would happen from natural exposure.

The second group was given ivermectin at the time in the life cycle that would kill the immature adults but not the adults. This group showed the pathology that occurs when the 2-inch-long immature adults die; the pathology that occurred was only due to immature adults, not to 6-inch-long adult worms.

The third group was infected while receiving selamectin. This group was to demonstrate the efficacy of this drug in preventing heartworm infections; its high efficacy was clearly demonstrated.

The following is a synopsis of what we now know about heartworm disease in cats.

Life Cycle
When a mosquito bites a cat, third-stage larvae (L3) are deposited on the cat’s skin. Within minutes they enter the subcutaneous tissue through the bite wound. The L3 molt within a couple of days to fourth-stage larvae (L4).

L4 migrate subcutaneously in fat and muscle for two months, then molt to become a juvenile or immature adult worm. (Immature adult worms have incorrectly been called L5 larvae.) Immature adult worms enter circulation via a peripheral vein. This occurs about 60 days after infection. An antibody response begins about this time; some cats test antibody positive.

Within the next 15 to 30 days -- 75 to 90 days post-infection -- the immature adult worms arrive in the pulmonary arteries. The vast majority of the juvenile worms die, are carried by blood flow into the lungs and cause an intense inflammatory response affecting the pulmonary arterioles, bronchi and alveoli.

It is estimated that about 3 to 4 percent of the immature adults become 6-inch-long adult heartworms and live for two to four years before dying spontaneously.

HARD
Heartworm associated respiratory disease, or HARD, is unique to the cat. You will not find it by studying heartworm disease in dogs. It is defined as vascular, airway and interstitial lung lesions caused by the death of immature adult worms, and the inflammation may last up to eight months.

If we administer 100 infective larvae to a dog, 75 will mature to adults. If we administer 100 infective larvae to a cat, many will become immature adult heartworms; however, only three to four will mature to adults. A very large number of immature adult worms develop but never make it to adulthood due to the effects of the cat’s immune system. Severe lung lesions are present but:

• No adult worms will be present on necropsy.
• The immature adult worms disintegrate within the lung tissue and are very difficult to find on necropsy.
• Antibodies disappear very quickly.
• Antigen tests will be negative because there have been no adults.

Radiographically, these cats may look similar to cats with allergic bronchitis. Interstitial or bronchial patterns may be present, and the caudal pulmonary arteries may be enlarged and blunted. In some cats, apparent enlargement may be due to periarterial inflammation. Repeated exposure to immature adult heartworms results in severe interstitial and bronchial disease. (See Figures 1,2)

It is no wonder that this disease has eluded detection until the Dillon and Blagburn study.

Incidence

3 Important Points By about three months post-infection, 2-inch-long immature adult heartworms are in the pulmonary arteries. . Most of these are killed by the immune system, never becoming adult heartworms. They are carried by blood flow into the lungs. . About 3 percent to 4 percent of the immature adults become 6-inch-long adult heartworms.

A large necropsy study in Gainesville, Fla., found that 5 percent of cats had adult heartworms², virtually the same incidence as FeLV and FIV infections. In the same group of cats, 15 percent were antibody positive. Interestingly, many that did not have adult heartworms present had signs of severe lung disease. In retrospect, what was observed was HARD, but at the time HARD was not understood.

In the 1997 Heska Heartworm Survey³, 15.9 percent of tested cats were heartworm-antibody positive. In the 1998 Miller, et. al. study⁴, 12 percent of tested cats, many from non-endemic areas, were antibody positive. Because many cats with HARD test antibody negative, the 12 to 16 percent incidence is probably much lower than the true incidence.

For every 10 heartworm-infected dogs in a given locale, one cat has adult heartworms. However, it is likely that only about 10 percent of heartworm-infected cats have an adult worm. That makes the exposure and infection rates of dogs and cats about the same.

Heartworm Testing

Antibody Tests

Antibodies are produced by the presence of immature adults, and they begin to wane as the immature adult worms die. If the immature adult worms mature to adults, the adult worms suppress the immune system, causing antibodies to dissipate. Most antibody tests turn negative about four months later as long as new infections do not occur.

A positive antibody test means one or more of these possibilities:

• A current infection with late L4.
• A current infection with immature adult heartworms.
• A current infection with adult heartworms.
• A previous heartworm infection. Antibody persists about four months.

Many cats with HARD are antibody positive and antigen negative. However, many test negative on both antigen and antibody tests, making differentiation from cats with allergic bronchitis virtually impossible.

Antigen Tests

A positive antigen test means (one or both):

• One or more adult female heartworms.
• One or more dying adult female heartworms.

Heartworm tests are inclusionary, not exclusionary. If they are positive, they are meaningful. If they are negative, they are not meaningful.

Antigen or antibody testing is not necessary to begin heartworm prevention because there is not a reaction between current heartworm prevention products and any stage of the heartworm.

Microfilaria Testing

In contrast to dogs, very few microfilaria circulate in cats. This test has very poor sensitivity in cats. This also explains why cats are very poor reservoirs for heartworm infections to other cats or to dogs.

Summary

• Positive antibody test: This cat is or has been infected with heartworms that progressed at least to the immature adult stage. It is clearly at risk of future infections
• Positive antigen test: This cat is infected with adult heartworms. It is clearly at risk of future infections.
• Microfilaria testing: This test has a very poor diagnostic yield.

Treatment of HARD
Most cats with HARD have mild coughing, but a severe respiratory crisis can occur when a large number of immature adult heartworms die at once. The treatment for the crisis cat is corticosteroids at shock doses: dexamethasone sodium phosphate (1-2 mg/kg IM or IV) or prednisolone sodium succinate (50-100 mg/kg IV) and a bronchodilator such as terbutaline. Oral prednisolone (1-2 mg/kg) or corticosteroid inhalers can be used prophylactically for inflammation.

These cats should be placed on a heartworm preventive product to prevent new infections.

Misnamed?
If we knew nothing about Dirofilaria immitis before the Dillon and Blagburn study, what common name would we have put on this parasite?

I seriously doubt we would call it a “heartworm.” Its normal locations in the cat are the pulmonary trunk and the left and right pulmonary arteries. Immature adults and adults are found in the heart only when the pulmonary arteries are filled with worms.

I was at a meeting of heartworm researchers and interested practitioners a few months ago. I suggested that we rename this parasite to better reflect its location in the cat and to make a break with the misunderstandings of the past. Not surprisingly, my idea was not well received. And I am not now on a campaign to change its name. However, it is important that we realize that this parasite does not follow the pattern of heartworms in dogs.

We all know that “cats are not small dogs.” We need to also appreciate that “cat parasites are not small dog parasites!”

What should we do now?
First, we need to appreciate what Dillon and Blagburn, with Pfizer’s financial backing, have done. Their study was one of the blockbusters in feline medicine.

Accolades also need to go to the “KNOW Heartworms” campaign of the American Assn. of Feline Practitioners. However, we must go past singing praises and move into action. This information needs to be shared with our clients, who must be motivated to act on it.

Create a handout for your clients endorsing heartworm prevention for all cats. Use the “KNOW Heartworms” materials in your exam rooms, and proactively use your annual examinations and other opportunities to talk to clients about this very important subject.

Clients need to know:

• Heartworm disease is much more common in cats than we thought. We have missed it because of a lack of understanding that we now have.
• Even with our new knowledge, heartworms are difficult to diagnose. Blood tests have severe limits on sensitivity.
• There is no good way to rid the cat of this parasite. It must die on its own.
• All cats should be on heartworm prevention using the same schedule as for dogs in that locale.
• Even indoor cats need to be included because about 25 percent of diagnosed cats are indoors only⁴.

Dr. Norsworthy, DVM, Dipl. ABVP (feline), owns and practices at Alamo Feline Health Center in San Antonio, Texas. He frequently speaks about cat health at veterinary conferences and seminars.

FOOTNOTES:

1. Dillon AR, Blagburn BL, Tillson DM, et. al. “Immature heartworm infection produces pulmonary parenchyma, airway, and vascular disease in cats” (abstract #133). J Vet Intern Med 2007;21(3):608-609.
   .
2. Levy JK, Snyder PS, Taveres LM, et. al. “Prevalence and risk factors for heartworm infection in cats from Northern Florida.” JAAHA 2003;39:533-537.
   .
3. Piché CA, Cavanaugh MT, Donoghue AR, Radecki SV. “Results of antibody and antigen testing for feline heartworm infection at Heska Veterinary Diagnostic Laboratories.” In: Seward RL, ed. Recent Advances in Heartworm Disease: Symposium ’98. Batavia, Ill: American Heartworm Society; 1998:139-143.
   .
4. Miller MW, Adkins CE, Stemme K, et. al. “Prevalence of exposure to Dirofilaria immitis in multiple areas of the United States.” In: Seward RL, ed. Recent Advances in Heartworm Disease: Symposium ’98. Batavia, Ill.: American Heartworm Society; 1998:161-166.

Soy May Aid In Treating Canine Cancers

Researchers at North Carolina State University are looking to soy as a way to make traditional canine cancer therapy more effective, less stressful for the dog and less costly for the owners. Dr. Steven Suter, assistant professor of oncology, and NC State colleagues studied genistein - a molecule found in soy that has been shown to be toxic to a wide variety of cancer cells in humans - to determine whether it would also inhibit the growth of canine lymphoma cells.
From:Veterinary News From Medical News Today

MU Discovery Could Help Identify Therapy For Humans And Cats With Forms Of Retinitis Pigmentosa

About one in 3,500 people are affected with retinitis pigmentosa (RP), a disease of the retina's visual cells that eventually leads to blindness. Now, a University of Missouri researcher has identified a genetic link between cats and humans for two different forms of RP. This discovery will help scientists develop gene-based therapies that will benefit both cats and humans.

حسادت در سگها

Test reveals dogs' jealous side

The dog handshake is initially rewarded with food

Scientists in Austria say they have found a basic form of jealousy in dogs.

The Vienna-based researchers showed that dogs will stop doing a simple task when not rewarded if another dog, which continues to be rewarded, is present.

Writing in the journal PNAS, the scientists say this shows a sensitivity in dogs that was only previously found in primates.

The researchers now plan to extend their experiments to look at co-operative behaviour in wolves.

The experiment consisted of taking pairs of dogs and getting them to present a paw for a reward. On giving this "handshake" the dogs received a piece of food.

One of the dogs was then asked to shake hands, but received no food. The other dog continued to get the food when it was asked to perform the task.

Reward value

The dog without the reward quickly stopped doing the task, and showed signs of annoyance or stress when its partner was rewarded.

To make sure that the experiment was really showing the interaction between the dogs rather than just the frustration of not being rewarded, a similar experiment was conducted where the dogs performed the task without the partner. Here they continued to present the paw for much longer.

The dog sees its partner rewarded

Dr Frederike Range from the department of neurobiology and cognition research at the University of Vienna, says this shows that it was the presence of the rewarded partner which was the greater influence on their behaviour.

"The only difference is one gets food and the other doesn't, they are responding to being unequally rewarded." she said.

The researchers say this kind of behaviour, where one animal gets frustrated with what is happening with another, has only been observed in primates before.

Studies with various types of monkeys and chimpanzees show they react not only to seeing their partners receiving rewards when they are not, but also to the type of reward.

The dog study also looked at whether the type of reward made a difference. Dogs were given either bread or sausage, but seemed to react equally to either. Dr Range says this may be because they have been trained.

"It's through the fact they have to work for the reward, this confers it with a higher value," she said.

Evolution

The researchers say this behaviour, reacting to others receiving rewards, may represent an earlier stage in the evolution of co-operative behaviours seen in human and primates.

"I think it's a precursor, simpler than in humans, it's a selfish behaviour, they don't react to seeing others treated unfairly. With humans they react, say it's unfair, we can't see anything like that in the dogs," said Dr Range.

The dog soon refuses to raise a paw

The researchers say the type of behaviour exhibited in the experiment is probably due to the dog's close association with humans. Dr Range says other animals need to be studied to really show how animals naturally exhibit jealousies or cooperate.

"I'm sure that it's not something that evolved with the dogs, we will have to test it in wolves and other cooperating species," she said.

Dr Range is currently rearing wolf cubs in order to perform similar experiments. She says the wolves will be able to do the paw test, but that it is really the wrong experiment. She regards this as something unnatural, that dogs are taught by their owners.

"They can give the paw, but it's not the right test. We must take the human out of the equation, then we can compare directly wolves with dogs."