Mosquitoes are small flies that belong to the family “Culicidae”. They were discovered by Sir Ronald Ross in 1902 during studies on malaria.
By Wajeeha Rafaqat, Dr. Muhammad Sohail Sajid, Dr. Urfa Bin Tahir, Mahvish Rajpoot
They bite and suck blood from humans, animals and birds. During biting, mosquitoes can transmit different types of pathogens such as parasites, viruses and bacteria. These microorganisms live in the blood of mosquitoes and are transmitted through their saliva. Diseases that are spread in this way are called mosquito-borne diseases. Mosquitoes love to live in environments. Natural habitats of mosquitoes are freshwater swamps, saltmarshes, woodland pools, catch basins, items in backyards, like discarded tires, clogged rain gutters or unmaintained bird baths and roadside ditches. Mosquitoes have four developmental stages; eggs, larvae, pupa and adults. An adult has three parts of the body; head, thorax and abdomen. A male mosquito lives for a very short duration (8-10 days), but a female mosquito can survive about 2-3 months. Climate change has a great impact on mosquito-borne diseases. Change in precipitation (above 10%) and temperature (26-29 c) increase the vector activities. Change in climate increases vector survival, replication of pathogens in the vector and biting rates of mosquitoes. Climate change decreases generation time for mosquitoes and hence supports rapid transmission.
Malaria:
Malaria is a fetal infection caused by the parasite “Plasmodium“. It is transmitted to the host by the bite of infected female Anopheline mosquitoes. It was first diagnosed in 21st century in primates of Africa. Mosquitoes cause malaria through four kinds of parasite species; P. falciparum, P. vivax, P. ovale, P. malarae and P. knowlesi. Parasite Plasmodium mainly infects hepatocytes and red blood cells of the body. Most of the malarial cases are reported in Sub-Saharan Africa and South Asia, but now it is prevalent in the whole world overall. WHO estimates that over 241 million malaria cases occur and 627,000 patients die of malaria each year. After 7-30 days of a mosquito bite, malaria causes signs and symptoms including fever, chills, nausea, vomiting, abdominal pain, jaundice, muscle aches, and yellow skin. No doubt Plasmodium infects people of any age, but children, pregnant women and individuals with destroyed immunity are most susceptible to malaria. In Pakistan, malaria is typically unstable with 37% incidence rate. Major transmission rates are observed from August to November and post mosoon. Antimalarial drugs and malaria control programms have been playing role in eradication of malaria in Pakistan. Currently, the malaria control is working in Pakistan along with National institute of Health (NIH) as parallel program to eradicate malaria in various endemic parts if the country.
Dengue:
Dengue is a viral disease caused by the “Flaviviridae” family of viruses with different serotypes, such as DENV-1, DENV-2, DENV- 3 and DENV-4. It is transmitted by the Aedes aegypti mosquitoes. Dengue fever is also called “breakbone fever. The global incidence of dengue is reported as over 100-400 million clinical cases each year. It mainly destroys the liver cells of a patient. It is found in urban and semi-urban areas of tropical and sub-tropical climates. Incubation period (time duration from the exposure of pathogen to the appearance of first symptom) for dengue virus is 5-7 days. Signs and symptoms are high fever, joint pain and severe headaches. This illness can progress to a hemorrhagic fever. There is no specific treatment for dengue but vaccines are available for prevention. Complete recovery from dengue fever immunizes the patient for the whole remaining life
Yellow fever:
Yellow fever is caused by arboviruses that belong to the genus Flavivirus. It is transmitted through Aedes mosquito bites. It is common in Sub-Saharan Africa and South America. It can infect people of any age, but elderly people are most vulnerable to this infection, developing severe yellow fever. Globally, 200,000 disease cases and over 30,000 deaths are reported each year. Incubation period for yellow fever virus is 3-6 days. It mainly infects the kidney, heart, liver and gastrointestinal tract. Yellow fever causes other signs and symptoms such as fever, liver failure, jaundice and kidney failure. A vaccine is available for yellow fever.
Zika virus disease:
It is caused by Flaviviruses and transmitted by Aedes mosquitoes. Outbreaks of this disease have been reported in Africa, Asia, America and the Pacific. Although the zika virus is reported in the neighboring countries, it has not been in Pakistan. The Vector of zika virus disease always bites during the day. Zika virus is also transmitted through the placenta from the infected mother to the fetus during pregnancy. Zika viruses mainly destroy brain cells. It shows symptoms after 3-7 days of a mosquito bite like mild fever, joint pain, rash and red eyes. Microcephaly (smaller head size) is the main outcome of infection in newborns. It is diagnosed by blood smears from an infected individual.
West-Nile virus disease:
It is caused by the Flaviviridae family and transmitted by mosquitoes. The West-Nile virus can infect humans, horses and birds. The first outbreak of this infection was reported in New York City. It is a seasonal disease. The West-Nile virus mainly infects people over 60 years of age. Globally, 2445 disease cases and 6.8% deaths are reported. After the incubation period (2-14 days), it destroys the nervous system of the patient. It has other signs and symptoms including fever, diarrhea, headache, skin rash, fatigue, vomiting and body aches.
Chikungunya disease:
Chikungunya are alpha viruses that belong to the family “Togaviridae”. Major outbreaks of this disease are reported in the Americas, Europe, Asia, Africa, the Indian and Pacific Oceans, and the Caribbean. Mosquitoes can bite during the day as well as during the night. No medicine and vaccine are available for chikungunya disease. Signs and symptoms appear after 5-10 days of a mosquito bite such as muscle pain, headache, joint rash or swelling.
Prospectives on MBDs in Pakistan:
Many factors offer suitable conditions, such as urbanization, colonization, unhygienic conditions, globalization, environmental pollution, destruction of natural ecology, travel and trade factors. Vector-borne diseases reach different areas of the world by travel and transport of-goods. These diseases can become epidemic or endemic. Moonsoon rainfall in Pakistan provides a suitable environment for mosquito growth. They can impact in direct and indirect ways on vector ecology and transmission. Many studies are conducted on mosquito borne diseases and their risk factors. Apart from these, we must improve public health measures. These measures are public awareness about vectors, real-time disease surveillance and monitoring, more entomological data and upgradation of laboratories for screening of pathogenic microorganisms. To improve the health care systems in Pakistan, we must promote the One Health approach by concerning all experts or professionals, such as veterinarians, physicians, environmentalists, educated civilians, concerned authorities to prevent the epidemic of diseases by mitigating risk factors. Many government, semi-government and private programs have been launched to mitigate mosquito-borne diseases, such as the Malaria control program (MCP), the Dengue control and prevention program, NIH, Infectious disease surveillance system in Pakistan, National Action Plan for Non-Communicable Disease (NAP-NCD), Field Epidemiology & Laboratory Training Program (FELTP).
Preventive measures for mosquitoes:
If you are traveling to places where the malaria is common, make sure to stay safe from the mosquito bites. Protection from mosquito bites is the only thing you can do to prevent the onset of disease. Also, chances of severity vary from individual to individual depending on their current condition and health records. Here are some of the preventive measures you can take to control the malaria and stop it from spreading further.
- Wear full sleeve protective
- Spray insect repellants on your exposed The recommended repellent contains 20-35% N N, N-Diethyl-meta- toluamide (DEET).
- When you go out, in addition to spraying insect repellants on your exposed skin, you can also spray on your Mosquitoes find it easy to bite through the thin clothing.
- Use a mosquito net over the bed if your bedroom is not air-conditioned and For additional safety, you can treat mosquito net with insecticide permethrin.
- Keep your home and surroundings clean without any any
- Make sure you don’t keep your doors and windows open at night as mosquitoes get active during the night and pose a higher risk. You can use a mosquito net to seal your window and then open for the whole time.
- When it comes to controlling the malaria, keep an eye out for symptoms like fever with high As soon as you find any possible signs of malaria, consult your physician immediately.
- Depending on condition and prescription, you can take the anti-malarial
- If you are a regular user of sunscreen, make sure you apply sunscreen first and then use an insect
- Follow the prescriptions of your This means that if your doctor has requested you to follow a 2-week course, follow prescription and medications for the two weeks.
- Currently, there is no over-the-counter medication available for So the only way you can treat this disease is by taking all the safety measures and necessary precautions.