Parasitic infection of the Intestine and Heartworms

What is Heartworm Disease?

Heartworm disease is caused by parasites and it can affect any dog irrespective of age, gender or environment. It is common in many parts of Australia. The carriers of heartworm parasites are mosquitoes and the prevalence of disease is high in areas prone to mosquitoes. Dogs are the parent host for heartworms. Other host animals for heartworm parasites include thirty different types of animals including foxes, cats, ferrets and very occasionally, humans.

Introduction to Heartworms

Heartworms reside in the heart blood of a dog and nearby blood vessels. They can extend 10-30 cm in length, are matured after 6 to 7 months of producing infection. Their life expectancy is normally 5 to 7 years. They reproduce within the heart and the young – called microfilariae – move around in the animal’s blood. The carrier female mosquito bites an infected animal and carries the blood with the microfilariae. When the same mosquito bites a healthy animal it transfers the larvae into the blood of that animal. At an early stage of infection in dogs, no signs may appear.

The infection caused by Heartworm is serious as it restricts the flow of blood, pressurises the heart and harms other body organs. The increase in stress and workload on heart increases its size, causing congestive heart failure. If left untreated, it is often lethal.

Screening of the blood can detect the presence of heartworms in blood. Ultrasound and X-rays are the means to diagnose the disease in later stages. Early detection and treatment is critical.

Cure and Prevention from Heartworm

Advances in vet science have made it possible to treat heartworm infections in dogs. Drugs called Adulticide and Microfilaricide can kill adult and young parasites. Prevention is always better than cure as it safe, easy, cheaper and kinder to your pet.

The available dosage forms are injections, topical applications for monthly use and chewable flavoured tablets to be used monthly. These medicines are used for prevention and are highly effective.

The most important thing to remember is to give your dog his annual shots as directed by your vet. Use of mosquito repellent is also helpful if you live in a place with mosquitoes to prevent unnecessary bites.

Symptoms of Heartworm Attack

  • Breathlessness
  • Cough
  • Lethargy and weakness
  • Low energy levels
  • Decrease in weight
  • Uneven and coarse fur coat

The Valuable Veterinarian Advice

The heart worm life cycle is dependent on local and climatic conditions, so it is very important to get a prescription from your vet before you give any medication to your pet. Self medication of your pet is not wise as only an expert can guide you as to the phases of the heartworm life cycle and transmission order followed in your particular area. You also need to observe the health and activity levels of your dog, paying attention to any changes.

When medicines are given for prevention purposes, dogs should be checked to see if they are carrying adult heartworms as these medicines can causes serious side effects in dogs who are positive carriers of adult heartworms. Routine tests are also suggested for dogs on prophylactic medicines to check the defence profile if in any case the dose has been missed.

Can Humans be Susceptible to Heartworm and Other Parasites?

Mosquitoes spread heartworms and not the pets. Humans are not the likely sources to carry heartworms so the chances of infection are minimal. The preventive medicines used for protection against heartworms can also aid in the control of other parasites including hookworms, roundworms, tapeworms and whipworms. Infections due to parasites which can easily be transmitted from animals to humans are called as Parasitic Zoonoses.

1. Hookworms

In dogs, hookworm infestation occurs by infiltration into the skin or ingestion of contaminated faecal material, as hookworm larvae are present in the faeces of an infected animal and the soil where the waste drops.

The larvae take up the journey towards the intestine and get themselves hooked to the intestine wall and start sucking the blood of the host. The hookworm larvae can also contaminate humans by penetrating through skin when they come in contact with polluted soil or waste material of host dogs and cats. In humans, the larvae do not suck blood by attaching themselves to the intestinal wall. Rather they move under the skin and die as a result of an inflammatory reaction initiated. This inflammatory response is called as cutaneous larva migrans or creeping eruptions. The best way to keep your pet free from hookworm is providing good hygienic conditions, prophylactic medicine and regular examinations by your vet. Do not allow stray dogs and cats access to your garden areas and other pet belongings.

2. Roundworms

As the name suggests they are round in shape, reside in a dog’s intestine and feed on partly digested food eaten by dogs. They do not attach to anywhere within the host, rather they are found floating freely in food. Adult and mature hookworms look like spaghetti and are expelled out in the faeces or vomit of an infected dog.

The transmission takes place in the form of eggs present in faeces that either pollute the soil or are ingested. Symptoms of hookworms infections are diarrhoea, vomiting and, in severe cases, pneumonia and intestinal bleeding. In humans, hookworms causes visceral larva migrans which a very serious illness. The most common fatalities are children when they lick contaminated fingers or other objects.

Once swallowed and taken in by the host, the hookworm larvae will complete its life cycle. The eye is the organ at the highest risk of hookworm damage, as they diffuse themselves in the eye and die. As a result of this inflammatory reaction in the eye, blindness can occur. Washing hands properly and frequently is the only prevention. De-worming the dogs and use of prophylactic medicines can help reduce environmental pollution.

3. Tapeworms

Many species of tapeworms can cause infection in dogs, and the mode of transmission varies with the species. Some are spread by fleas or by eating infected uncooked meat. The symptoms produced by tapeworms are of varied intensity such as malaise, mild colic, and diarrhoea. The appearance of symptoms also depends on the age and health of the diseased dog.

In humans, only certain species can be transmitted via rotten eggs present near dog faeces, but if ingested, these may cause very serious consequences. The preventive measures include medicines for protection, de-worming animals, flea control and not feeding your dog unrefined, untreated meat. All these precautions can prevent transmission in both dogs and humans.

4. Whipworms

The only source of contracting whipworms is when a dog ingests its eggs. Whipworm eggs are widely spread over the soil and ground making it contaminated. When the dog walks over the infected eggs, they carry them via their paws. They later lick their paws and other objects like toys or food carriers and ingest the eggs by mouth. The eggs can live in extreme severe climatic conditions for months and years. The hatching of eggs begins within 1 to 3 months of ingestion in the dog’s intestine. They attach themselves to the intestine wall, suck blood and the reproduction cycle continues. The symptoms in dogs are diarrhoea; decrease in weight, and in some cases anaemia. Whipworms rarely affect humans.

Stay Safe and Sound

Children are in closer physical contact with pets, making them more susceptible to zoonotic parasites. Parasite larvae are left behind in pet faeces and pollute the soil and surrounding areas. Children playing in the similar regions can easily carry them on their fingers. They may later put their fingers in their mouth and ingest and catch infections. Hookworm larvae infects the host by infiltrating through skin. Be very careful to clean the waste area properly and regularly and do not let children eat while playing with pets. Other safety measures include washing hands and good hygiene for both pet and owner. Visit your vet on a regular basis and if recommended, follow investigative tests to determine if any parasitic infestation has occurred or is occurring. A physical examination and preventive medicines all together can help you keep your pet and family safe from such parasites.