World Mosquito Day, Female Anopheles Mosquitoes, Malaria, Sir Ronald Ross’s Most Important Discovery

World Mosquito Day: This Day honors the date when Sir Ronald Ross, a British army surgeon working in India, proved that mosquitoes transmit malaria by identifying pigmented malaria parasites in mosquitoes that fed on an infected patient. This discovery revolutionized our knowledge of the disease and led to new preventive measures. Ross won the Nobel Prize for Physiology or Medicine in 1902.

World Mosquito Day

This day observed annually on 20 August, is a commemoration of British doctor Sir Ronald Ross‘s discovery in 1897 that female anopheline mosquitoes transmit malaria between humans.

Malaria is a disease that mosquitoes carry, which is caused by a parasite. It is curable and preventable, yet sadly, it still threatens the lives of millions of people across the globe. It is important to note that, not all mosquitoes transmit this disease; only infected female anopheles are able to transmit this to humans.

The latest statistics show that approximately 435,000 people die of this disease every year. Not only this, but there is believed to be approximately 219 million cases of this mosquito borne disease every year across the world.

This disease can be found in over 100 countries. It is a condition that typically impacts the world’s tropical areas. Nevertheless, roughly 70 percent of the malaria burden around the world is concentrated in 11 countries. One being India, and the rest being on the African continent.

Malaria

Malaria is a mosquito-borne infectious disease that affects humans and other vertebrates. In Human this disease causes symptoms that typically include fever, fatigue, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. Symptoms usually begin 10 to 15 days after being bitten by an infected mosquito. If not properly treated, people may have recurrences of the disease months later. In those who have recently survived an infection, reinfection usually causes milder symptoms. This partial resistance disappears over months to years if the person has no continuing exposure to malaria.

It is spread exclusively through bites of infected Anopheles mosquitoes. The mosquito bite introduces the parasites from the mosquito’s saliva into a person’s blood. The parasites travel to the liver where they mature and reproduce. The risk of disease can be reduced by preventing mosquito bites through the use of mosquito nets and insect repellents or with mosquito-control measures such as spraying insecticides and draining standing water.

Vaccines

There are vaccines that prevent this mosquito-borne infectious disease which annually affects an estimated 247 million people worldwide and causes 619,000 deaths. The first approved vaccine for this disease is RTS,S, known by the brand name Mosquirix. As of April 2023, the vaccine has been given to 1.5 million children living in areas with moderate-to-high transmission. It requires at least three doses in infants by age 2, and a fourth dose extends the protection for another 1–2 years. The vaccine reduces hospital admissions from this severe mosquito borne disease by around 30%.

Research continues with other vaccines. The most effective vaccine is the R21/Matrix-M, with a 77% efficacy rate shown in initial trials and significantly higher antibody levels than with the RTS,S vaccine. It is the first vaccine that meets the World Health Organization’s (WHO) goal of a malaria vaccine with at least 75% efficacy. In April 2023, Ghana’s Food and Drugs Authority approved the use of the R21 vaccine for use in children aged between five months and three years old. Following Ghana’s decision, Nigeria provisionally approved the R21 vaccine.

Tests

There are several tests to diagnose this disease. There are different types of parasites causing this deadly disease that infect humans. The tests can tell which type you have. This information is important for choosing the right treatment to cure the disease.

The testing is also used to help control the spread of the disease. That’s because mosquitos become infected with the parasites when they bite a person who is suffering from this disease. Then they spread the disease by biting others. Testing helps you get treatment to get rid of the parasites before more mosquitos get the parasite by biting you.

Depending on the type of parasite, symptoms usually begin between 7 to 30 days after an infected mosquito bites you. But symptoms can take up to a year to appear. So, if you have symptoms, remind your health care provider about any places you’ve traveled over the past 12 months.

The first symptoms of this mosquito borne disease are often like having the flu, and may include:

• Fever
• Chills
• Fatigue
• Headache
• Muscle pain
• Nausea and vomiting

If you are infected with certain types of malaria parasites, you may have symptoms which come and go every two or three days.

Without treatment, The disease can quickly become a life-threatening disease. As it gets worse, the symptoms will depend on the type of parasite you have. They may include:

• Anemia
• Jaundice
• Kidney failure
• Seizures
• Mental confusion
• Coma

During a blood test, a health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

There are two types of blood tests to diagnose malaria. Both tests are done when possible:

• Blood smear test. For this test, a drop of your blood is put on a special slide. A laboratory professional will examine the slide under a microscope to look for parasites. This test can identify all types of malaria parasites.
• Rapid diagnostic test (RDT). This test looks for certain proteins that come from malaria parasites. It can provide results in under 15 minutes, but an RDT can’t accurately show which type of malaria parasite you have. This information affects your treatment. So, if an RDT shows that you have malaria, a blood smear is needed, too.

Your provider may order other blood tests, such as a complete blood count (CBC). If you do have malaria, the results of these tests will show how the disease is affecting you.

Most Important/Unknown Facts

1. Among all communicable diseases, malaria is the third largest killer of children between the ages of one month and five years, following pneumonia and diarrhea.
2. Nearly 300,000 children under the age of five die of malaria died in 2016 equivalent to nearly 800 young lives lost each day.
3. In the years between 2000 and 2015, the mortality rate fell by 60% and the number of cases dropped by 37% globally. During those 15 years, 6.2 million deaths were averted, including the deaths of 5.9 million children under five.
4. Malaria is caused by Plasmodium parasites. The parasites are spread to people through the bites of infected Anopheles mosquitoes, called “malariavectors”, which bite mainly between dusk and dawn.
5. There are four Malaria parasite species that cause malaria in humans:→ Plasmodium falciparum
   → Plasmodium vivax
   → Plasmodium malariae
   → Plasmodium ovale (curtisi, wallikeri)
   → Plasmodium knowlesiPlasmodium falciparum and Plasmodium vivax are the most common. Plasmodium falciparum is the most deadly. Malaria parasites live in the red blood cells of infected people. When mosquitoes bite an infected person, they pick up the parasite. The next person the mosquitoes bite can get infected. The parasites first go to your liver to mature and reproduce. Then the parasites go into your blood and reproduce inside your red blood cells. Eventually the red blood cells burst and release the parasites, which then infect more red blood cells. If many red blood cells are destroyed, you can get a low blood count (anemia). 

   

   World Malaria Day celebrated on 25th April every year is an occasion to highlight the need for continued investment and sustained political commitment for prevention and control of this deadly disease. It was instituted by WHO Member States during the World Health Assembly of 2007.

6. The most dangerous form of this disease is called falciparum malaria. Falciparum malaria is especially dangerous because the infected red blood cells can clog up tiny blood vessels and cause organ damage. They may damage your brain, kidney, lungs, and other organs. Other forms don’t do this.
7. It is one of the major world public health problems, causing 350-500 million infections worldwide and approximately 1 million deaths annually. The transmission occurs in large areas of Central and South America, Africa, Asia, Eastern Europe, and the South Pacific. In endemic areas such as tropical Africa, the incidence is higher in children younger than five years, due to low acquired immunity.
8. WHO recommends anti-malaria bed nets as the most effective and inexpensive way to prevent this disease.
9. The word “Malaria” means bad air.
10. In 2021, nearly half of the world’s population was at risk of this deadly disease.
11. That year, there were an estimated 247 million cases worldwide.
12. The estimated number of deaths stood at 619 000 in 2021.
13. The WHO African Region carries a disproportionately high share of the global malaria burden. In 2021, the Region was home to 95% of cases and 96% of deaths. Children under 5 accounted for about 80% of all deaths in the Region.
14. According to the latest World malaria report, there were 247 million cases of this disease in 2021 compared to 245 million cases in 2020.
15. The estimated number of deaths stood at 619 000 in 2021 compared to 625 000 in 2020.
16. Over the 2 peak years of the pandemic (2020–2021), COVID-related disruptions led to about 13 million more cases and 63 000 more deaths.
17. Four African countries accounted for just over half of all malaria-deaths worldwide: Nigeria (31.3%), the Democratic Republic of the Congo (12.6%), United Republic of Tanzania (4.1%) and Niger (3.9%).
18. In 2021, 35 countries reported fewer than 1000 indigenous cases of the disease, up from 33 countries in 2020 and just 13 countries in 2000.
19. Countries that have achieved at least 3 consecutive years of zero indigenous cases of malaria are eligible to apply for the WHO certification of malaria elimination.
20. Since 2015, 9 countries have been certified by the WHO Director-General as malaria-free, including Maldives (2015), Sri Lanka (2016), Kyrgyzstan (2016), Paraguay (2018), Uzbekistan (2018), Argentina (2019), Algeria (2019), China (2021) and El Salvador (2021).

The WHO Global technical strategy for malaria 2016–2030, updated in 2021, provides a technical framework for all malaria-endemic countries. It is intended to guide and support regional and country programmes as they work towards the control and elimination of this disease.

The strategy sets ambitious but achievable global targets, including:

• reducing malaria case incidence by at least 90% by 2030
• reducing malaria mortality rates by at least 90% by 2030
• eliminating malaria in at least 35 countries by 2030
• preventing a resurgence of malaria in all countries that are malaria-free.

 

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