Blood parasites are organisms that survive in the blood of their animal hosts. There are a wide variety of blood parasites, ranging from single-celled protozoa to more intricate bacteria and rickettsiae. Though the transmission mode of these parasites varies greatly, it is mainly dependent on the parasite itself. The bites of ticks or flies are some of the ways the parasite is spread.
Babesiosis is a disease that is spread primarily by ticks. Protozoan parasites of the genus Babesia are the known causative agent, infecting the body’s red blood cells. A variety of household and wild animals are usually affected by Babesiosis, although humans can sometimes succumb to it. Although the chief financial effect of Babesiosis is on the cattle industry, dogs are also infected at diverse rates all over the world.
There are a variety of signs that indicate infection, ranging from mild illness that clears up rapidly to severe disease that quickly results in fatality. There are also situations where the parasite causes a long-term disease whose main symptom is severe and progressive anaemia. Sometimes there can be confusion between Babesiosis and other similar ailments that bring about fever, anaemia, destruction of red blood cells, jaundice, or red urine. It is thus imperative that laboratory tests be conducted in order to ensure the correct diagnosis.
It is possible to obtain proper medication prescribed by your veterinarian. Anti-inflammatory drugs, antioxidants, and corticosteroids can also be beneficial in boosting this treatment. When it comes to extremely anaemic animals, blood transfusions could be the difference between life and death.
A vaccine is available for the strain of Babesia found in Europe, but unfortunately, it doesn’t protect against the other strains. Effective control and quick elimination of ticks is the most important way of preventing exposure of your dog to this parasite.
Although there have been a few noted cases of human Babesiosis, there is no certainty as to whether the species of Babesia that affects dogs is the same one that infects humans. There have been reported fatalities in people who had their spleen removed, or who had weak immune systems. Bites from infected ticks and contaminated blood transfusions are the modes of transmission for most human Babesia infections.
Hepatozoonosis is a disease caused by a protozoan known as Hepatozoon Canis, and affects wild and domestic carnivores. This organism is spread by the brown dog tick, though it has an unusual transmission mode. The tick acquires the organism when it bites an infected host. A healthy dog acquires the disease when it ingests the tick instead of from a tick bite. In the North American region, the signs infected dogs display are totally different and more severe than the rest of the world. In fact, in North America the disease results from a different Hepatozoon species, named Hepatozoon americanum. This particular species is spread by the Gulf Coast tick and not the brown dog tick. Due to these variations, the infection in North America is known as American canine hepatozoonosis.
In a lot of places around the world i.e. India, Africa, Southeast Asia, the Middle East, southern Europe, and islands in the Pacific and Indian Oceans, dogs that are infected don’t display any signs of infection or only show mild signs. A compromised immune system due to another ailment seems to be a considerable factor in the development of major signs. More severe signs are commonly experienced in the United States. The states in the US with the most diagnosed cases are Texas (mainly along the Gulf Coast), Oklahoma, and Louisiana, although there are notable cases as far east as Tennessee, Alabama, Georgia, and Florida. This is a new disease that has largely extended north and east from the Gulf Coast of Texas, where it was first diagnosed in 1978.
Although dogs that are older than 4 to 6 months of age are typically immune to infection with H. Canis, the H. americanum strain shows severe signs even in adult dogs.
American Canine Hepatozoonosis
An animal infected with H. americanum develops inflamed body tissues which results in signs of disease like fever, depression, loss of weight, poor body condition, muscle atrophy and weakness, discharge from the eyes, and blood-spattered diarrhoea. The fevers may be erratic, ranging from 102.7 to 106°F (39.3 to 41.0°C). These signs are intermittent and most affected dogs surprisingly maintain a normal appetite. The more typical signs are extreme sensitivity near the vertebrae, rigidity and a general unwillingness to move. Ultimately, hepatozoonosis may cause kidney inflammation or amyloidosis of the kidneys, which is accumulation of the abnormal protein (amyloid) in the kidney tissues.
There are precise medical tests available that can be performed by a veterinarian to verify the presence of this disease. Other laboratory tests may show a considerable elevation in white blood cell numbers and a mild to moderate anaemia. Making a diagnosis can also be aided by using muscle biopsies.
Hepatozoonosis is disease that stays with an infected dog for life, as there is no existing medication that totally eliminates the organism from the body. Majority of infected dogs previously displayed temporary improvement in health, with the disease recurring within 3 to 6 months and death within 2 years of diagnosis. Nonetheless, new combinations of drugs help improve remission rates. These innovative therapies have brought about a clear improvement in the outlook for dogs with hepatozoonosis.
The most effective way to control this disease is to keep your dog away from ticks. Ensure that you have in place good tick control, particularly if you reside in an area prone to the disease. Humans are not at risk of getting this disease from animals.
African Tsetse-transmitted Trypanosomiasis
Tsetse flies are tiny, winged insects that bite and suck the blood of both humans and animals. They are native to sub-Saharan Africa, where they spread a set of protozoan diseases of the genus Trypanosoma. Tsetse flies are limited to the African continent, though other locations such as Central and South America have horseflies and biting flies that can transmit the disease. The most probable cause of this disease in dogs is Trypanosoma brucei. Since Trypanosoma mainly affects domestic animals, these may be a cause of human infections.
Tsetse flies that have been infected with the protozoa proceed to inject them into the skin of animals, where they develop quickly and cause local swelling known as chancres. They then penetrate the lymph nodes and enter the bloodstream, where they reproduce rapidly. Although the immune system reacts strongly, some trypanosomes tend to be resistant to the immune response, resulting in long-term infection.
How severe the disease is will depend on the species of the affected animal, its age, and the species of trypanosome involved. Dogs may develop the disease rather quickly, although the incubation period is typically 1 to 4 weeks. The key symptoms to look out for are fever, anaemia, and drop in weight. Other signs may include the eyes, and the lymph nodes and spleen might become swollen. Identification of trypanosomes in an infected dog’s blood is typically confirmed via laboratory tests.
Although there are many drugs available for treatment of the disease, it is important to note that most drugs will only be effective if the proper dose is administered. There are situations where the infected animal doesn’t respond to treatment, which may be attributed to trypanosomes that have become resistant to certain drugs.
Minimising the chances of infection in areas with high prevalence rates is possible only if dogs are kept indoors, preventive drugs are administered, or tsetse flies are eliminated. It is worth noting that dogs are rarely given preventive drugs. Flies can be moderately kept in check by using sprays or dips on the pets, spraying insecticides on breeding areas, using insecticide-coated screens, and cutting brush to destroy the flies’ habitat. A vaccine does not exist for treating this disease.
Surra (Trypanosoma evansi Infection)
Surra is distinct from diseases spread by the tsetse fly because it is generally transmitted by other biting flies, either within or outside tsetse fly areas. It is prevalent in North Africa, the Middle East, Asia, the Far East, and Central and South America. Though it mostly affects horses, all domestic animals are vulnerable to the disease. It can be fatal, especially in horses and dogs. Its progression, effects, symptoms, physical changes, diagnosis, and treatment are comparable to those of the tsetse-transmitted trypanosomes.
Chagas’ Disease (Trypanosoma cruzi Infection)
Chagas’ disease is a result of infection with another trypanosome. Insects spread this disease among vulnerable species of animals, such as opossums, armadillos, rodents, and undomesticated carnivores. Humans, young dogs and even cats are sometimes also infected with the disease. The disease is native to Central and South America, and specific areas of southern US. Domestic animals that get infected may bring in the trypanosome into homes that have the insects; causing people to become infected though contamination of wounds, or by ingesting food contaminated with insect droppings that carry trypanosomes. Other domestic animals operate as disease-carriers without necessarily displaying any symptoms of illness. Dogs that have been infected may pass away unexpectedly or experience short- or long-term inflammation of the cardiac muscle.