Where there are mosquitoes, there may be heartworm
Heartworm disease is a serious disease of domestic nursing pets. The main infected pets are dogs, cats and ferrets. When the worm matures, it mainly lives in the heart, lungs and related blood vessels of animals. When the worm grows up and causes disease, there will be serious lung disease, heart failure, injury and death of other organs.
Heartworm is a strange bug. It cannot be directly transmitted between dogs, cats and cats, dogs and cats. It must be transmitted through an intermediary. In the United States, heartworm disease is spread in all 50 states, but it is mainly concentrated in the Gulf of Mexico, the Mississippi River Basin and other places, because there are many mosquitoes in these places. There are cases of infection in all parts of our country, and the infection rate in some areas is more than 50%.
Dogs are the ultimate host of heartworm, which means that only heartworm living in dogs can mate and produce offspring. In particular, people will not be infected with heartworm from pets. Only in rare cases, people may be infected with heartworm after being bitten by infected mosquitoes. However, because people are not the host, the larvae usually die before migrating to the arteries of the heart and lungs.
Growth of heartworm in dogs
Adult heartworm lives in the cardiovascular system of dogs. Female adults give birth to microfilariae, and the eggs flow to various parts with the blood. However, these microfilariae cannot continue to develop, and they need to wait for the arrival of mosquitoes. When a mosquito bites an infected dog, it is also infected with microfilariae. In the next 10-14 days, when the environment and temperature are appropriate and the mosquito is not killed, the microfilariae grow into infectious larvae and live in the mosquito. The infectious larvae can only be transmitted to the dog by biting until the mosquito bites another dog again.
It takes 6-7 months for infective larvae to develop into adult heartworm. The adults mate again, and the females release their offspring into the dog's blood again to complete the whole cycle. The life span of adult heartworms in dogs is about 5-7 years. Males are about 10-15cm long and females are 25-30cm long. On average, there are about 15 heartworms in infected dogs, up to 250. The specific number of worms is generally judged by the worm burden. Through the equipment to test the blood, the antigen test can accurately detect the number of female adults in the dog, and the microfilaria test can confirm that there are not only adults but also larvae in the dog.
There are some standards for heartworm inspection in the United States: the first inspection of heartworm can start after the dog is 7 months old; Pet owners have forgotten the last time to prevent heartworm; Dogs are changing commonly used heartworm prevention drugs; Recently, I took my dog to the common area of heartworm; Or the dog itself lives in the common area of heartworm; After the examination, the prevention of heartworm will begin.
Symptoms and prevention of heartworm infection in dogs
The severity of heartworm disease is directly related to the number of worms in the body (worm burden), the length of infection and the physical fitness of dogs. The more worms in the body, the longer the infection time, the more active and robust the dog is, and the more obvious the symptoms are. In the United States, heartworm disease is divided into four grades. The higher the grade, the more serious the disease is.
Grade 1: asymptomatic or mild symptoms, such as occasional cough.
Grade 2: mild to moderate symptoms, such as occasional cough and fatigue after moderate activity.
Grade 3: more serious symptoms, such as physical fatigue, illness, persistent cough and fatigue after mild activity. Signs of difficulty breathing and heart failure are common. For grade 2 and 3 cardiac filariasis, changes in the heart and lungs are usually seen on chest X-rays.
Grade 4: also known as vena cava syndrome. The burden of worms is so heavy that the blood flowing back to the heart is blocked by a large number of worms in the blood vessels. Vena cava syndrome is life-threatening. Rapid surgical resection of heartworm is the only treatment option. Surgery is a risk. Even if it is surgery, most dogs with vena cava syndrome will eventually die.
FDA approved that melassomine dihydrochloride (trade names immicide and diroban) can be injected to treat heartworm of Grade 1-3. The drug has large side effects, and the overall treatment cost is expensive. Frequent tests, X-rays and drug injections are required. For the removal of microfilariae, FDA approved another drug, advantage multi for dogs (imidacloprid and moxikeding), namely "aiwalker".
In the United States, all drugs approved by FDA to prevent heartworm are prescription drugs, including drops and oral tablets applied to the skin (Ewok, big pet, dog Xinbao, etc.), because heartworm prophylaxis will not kill adult heartworm, but heartworm prevention for dogs infected with adult heartworm may be harmful or fatal. If microfilaria is in the dog's blood, preventive measures may lead to the sudden death of microfilaria, triggering a shock like reaction and possible death. Therefore, it is necessary to carry out the prevention test of heartworm every year under the guidance and advice of doctors. "Worship Chong Shuang" is an insect repellent with a sharp edge. It does not directly target microfilariae, but tries to avoid mosquito bites and cut off the transmission line from the middle, which is indeed a lot safer.
Basically, prevention of heartworm disease is more important than treatment. As can be seen from the growth cycle of heartworm described above, mosquito cultivation is the most critical link. Health can be guaranteed only by cutting off mosquito bites. This will be much better for long haired dogs, while short haired dogs need more attention.
Post time: Mar-23-2022