There are several types of hookworm that can cause disease in dogs. The main cause of canine hookworm disease in most of the tropical and subtropical areas of the world is Ancylostoma caninum. The main cause of canine hookworm disease in cooler areas is Uncinaria stenocephala. There are other canine hookworms such as Ancylostoma braziliense, which is found in some areas of the United States of America, Central America, South America and Africa.
The eggs of hookworms are passed in the fecal matter between fifteen and twenty days after infection. They can hatch in two to three days when deposited on moist, warm soil. They can be transmitted through the ingestion of larvae, or in the case of Ancylostoma caninum, from the colostrum and milk of nursing mothers who have been infected. The Ancylostoma species can also infect the animal through a larval invasion through the skin. If the larvae invade a young pup through its skin, they will migrate through the bloodstream to the lungs. They are then coughed up and swallowed. They enter the small intestine and mature there. If the animal is older than three months, the larvae can remain in the tissues of the body without the larvae developing any further. The larvae can be activated during pregnancy, when they move to the mammary glands, or when the adult worms have been removed.
The main symptom of Ancylostoma caninum in puppies is anemia. It can be fatal in young puppies. Anemia occurs because of how hookworms feed. They change the site that they are feeding at which leaves open internal wounds. The result of this is that the puppy is losing blood through the hookworm sucking the blood and through the internal bleeding that they leave behind. Puppies who survive can have some immunity and show milder symptoms. If the animal is malnourished or weak, it may grow poorly and suffer from long term anemia. Dogs who are well nourished and mature may have a few hookworms without showing any symptoms. They can be a source, either direct or indirect, of infection for puppies. The symptoms of severe infection includes diarrhea with dark, tar like feces. The symptoms of long term disease are anemia, weakness, and weight loss. It is possible for extremely severely infected pups to develop pneumonia which will make breathing difficult.
The other common hookworms do not tend to cause anemia. Despite this, the level of blood protein can reduce by more than ten per cent due to blood fluid loss around the attachment site in the intestine. It is possible for the animal to have dermatitis sue to larval invasion through the skin if the animal is infected with Ancylostoma braziliense.
Diagnosing hookworms can be done by identifying the type of hookworm eggs in the fecal matter of infected dogs. Despite the severity of the infection, it will take around sixteen days for the worms to produce eggs. Therefore, it is possible for a young pup to have anemia or even die from an infection passed through the mother via nursing before any eggs are visible in a fecal examination. This can happen as young as one of two weeks old.
There are many drug programs, or a combination of drugs, available for treating hookworms. Heart worm medication can control certain hookworm species. It may be necessary for the animal to have a blood transfusion or an iron supplement if it has severe anemia. This will need to be followed by a high protein diet until the hemoglobin level has returned to normal. If newborn puppies die from a hookworm infection, any future litter from the same mother will need to be treated twice a week for around twelve weeks. This should start when the pups are one or two weeks old. The veterinarian may prescribe an appropriate daily medication for the mother. This should begin at day forty of the pregnancy until day fourteen after the litter has been born.
Female dogs should be hookworm free before bedding and denied access to any contaminated areas while pregnant. The housing and bedding of pregnant females must be cleaned regularly and kept as sanitary as possible. The veterinarian may recommend a disinfectant to add to the water for cleaning bedding or cleaning solutions for the housing. If the outside area is a concrete runway, it should be washed twice weekly. If the outside area is clay or sandy, they can be decontaminated with sodium borate.