The most dangerous animal in the world that can be crushed with a quick strike is the mosquito.

Buzzing insects are more than just annoying - they spread diseases. When they bite and drink the blood of a person or animal, they can also pick up viruses or germs. If they manage to bite a person or something else, they deposit the germ directly under the skin.

People in some areas of Massachusetts have been warned to stay indoors when mosquitoes are most active after a rare case of Eastern Equine Encephalitis was discovered. Dr. Anthony Fauci, the former infectious disease expert in the United States, was also hospitalized recently after contracting the West Nile Virus.

Both are serious diseases spread by mosquitoes - although fortunately, they are relatively rare.

The best way to avoid getting sick is, of course, to avoid mosquito bites, which means taking steps like using mosquito repellent, wearing long-sleeved shirts and long pants, and staying indoors when mosquitoes are outside. Local health departments are also working to reduce mosquito populations, including spraying neighborhoods with insecticides. Authorities in Massachusetts are using trucks and planes this week to spray at-risk areas.

Here's a look at some common - and uncommon - diseases transmitted by mosquitoes.

Eastern Equine Encephalitis

Most people infected with Eastern Equine Encephalitis do not show symptoms, but some may develop fever or brain swelling, and about a third of those infected die. According to the Centers for Disease Control and Prevention in the United States, there have been three cases of Eastern Equine Encephalitis in the United States this year, one each in Massachusetts, New Jersey, and Vermont. The worst year for the disease was 2019, when there were 38 cases. It is caused by a virus and is not very common worldwide. The virus typically spreads in certain marshes, including red maple and white cedar swamps in Massachusetts.

West Nile Virus

Around two in ten people infected with the West Nile Virus show symptoms, which can include fever and brain swelling. About one in ten people with severe symptoms die. There have been 216 cases of West Nile Virus so far this year. West Nile Virus was first reported in the United States in 1999 in New York and has gradually spread across the country. In 2003, there were nearly 10,000 cases.

Malaria

Malaria infected nearly 250 million people worldwide in 2022 and killed more than 600,000, most of whom were children. It is caused by a parasite carried by mosquitoes and primarily affects people in tropical regions, especially Africa. A vaccination campaign has been launched in recent months that health officials hope will help reduce cases and deaths.

Dengue Fever

Dengue fever is also known as "breakbone fever" because it can be extremely painful, and it has become more common. The World Health Organization states that about half of the world's population is at risk of the disease, with 100 million to 400 million infections each year. Not everyone shows symptoms, which can include fever, severe headache, and pain in muscles and joints. Most cases in the United States have been among people who traveled to other countries, although the Centers for Disease Control and Prevention say there have been about 2,600 locally acquired cases so far this year.