How many kinds of mosquitoes are there?
There are roughly 3,500 species of mosquitoes known, but the total number in existence may exceed 4,000. Among all of those species, there is staggering diversity in the strategies they use to breed, feed and survive.
How does a mosquito transmit dengue virus to a person?
An infection can occur after a single bite. A female mosquito that takes a blood meal from a person infected with dengue fever becomes infected with the virus in the cells lining its gut. About a week later, the virus spreads to other tissues, including the mosquito’s salivary glands, and is subsequently released into its saliva. Unharmed by the virus, the mosquito will remain infected for the rest of its brief life (typically one month).
How do you know if you have dengue fever? What are the symptoms?
Dengue virus infection usually causes a fever with intense joint pain, and sometimes rash. This has been described as "break bone fever" because you feel as though your joints are going to come apart. Symptoms last for about two weeks. Then you recover and feel better. Rarely, dengue fever can become more serious and even deadly. In these cases, the host not only develops fever-like symptoms, but also hemorrhagic lesions throughout their body, which if untreated can cause severe bleeding, shock and eventually death. This severe form of the disease is more likely to develop if the person has been infected with dengue before. There are four serotypes of dengue, so theoretically a person may be infected up to four times.
Are viruses alive?
It’s suitable to talk about viruses as living organisms because they perform the two essential functions of life: evolution and replication. The difference is that they borrow a toolkit from their host to do so. They’re incredibly successful–every life form on Earth is infected by viruses.