There's an African proverb that says, “If you feel too small to make a difference, try sleeping in a closed room with mosquitoes.”
What comes to mind when you read this? How can a human be smaller than a mosquito? How can we not combat mosquitoes? However, mosquitoes are, in fact, one of the deadliest animals in the world. People are often taken aback when they learn that mosquitoes are the deadliest animals globally, despite their size, less than 2 centimeters in length and a mere weight of 2.5 milligrams.
In fact, the female mosquito is responsible for more deaths than any other animal, primarily due to its ability to transmit infectious diseases such as dengue fever, yellow fever, filariasis viral encephalitis (like West Nile virus), and most notably, malaria. Malaria alone accounts for more than 90 percent of mosquito- related fatalities.
There are four species of Plasmodium parasites that reside in humans: Plasmodium vivax, Plasmodium malaria, Plasmodium falciparum, and Plasmodium ovale. When a mosquito bites a person, it injects sporozoites into the body along with its saliva. These sporozoites enter liver cells through the bloodstream. In many instances, the sporozoites remain dormant within the liver cells for days, weeks, or even months before progressing to the next stage of their life cycle. The four Plasmodium species exhibit varying asymptomatic incubation periods. Once activated, the parasite starts multiplying inside liver cells, causing them to rupture and release sporozoites, which are parasite cells. These merozoites then invade the host's bloodstream and infiltrate red blood cells (RBCs). Inside the red blood cells, the parasite undergoes significant expansion, absorbs the hemoglobin of the RBCs, and undergoes multiple rounds of reproduction. Eventually, the infected red blood cells burst, releasing a wave of new merozoites capable of infecting more red blood cells. This cycle of infection, growth, reproduction, and release occurs every 2-3 days (depending on the parasite species) until the patient is either treated or succumbs to the disease.
Malaria stands as one of the deadliest diseases globally, infecting approximately 300 million people each year and causing around 430,000 fatalities. The majority of cases and deaths (over 90 percent) occur in sub-Saharan Africa, with a significant proportion affecting children under the age of five. Additionally, malaria is prevalent in various other warm and tropical regions that experience abundant rainfall and serve as breeding grounds for mosquitoes. These regions include parts of Asia (such as China, India, and Southeast Asia), Central America, and the northern regions of South America. Malaria is nearly ubiquitous in impoverished tropical areas, resulting in a weakened workforce, severely restricted productivity, and hindering economic, individual, and social development. The impact of malaria is far-reaching, with reduced productivity among individuals, increased school dropout rates, and imposing significant financial burdens on families, compelling them to allocate limited resources to healthcare. Numerous public health experts consider malaria to be one of the major obstacles in breaking the perpetuating cycle of poverty in developing nations.
The Roman writer Marcus Trentius Varo proposed that small insects found in damp conditions may have contributed to the spread of diseases. Roman officials recognized that excessive water had a detrimental impact on the health of the city's residents, prompting them to initiate the construction of a vast underground sewer system known as the Maxim Sewer. This ambitious public works project aimed to drain floodwaters and wastewater from Rome, and it became one of the most groundbreaking and progressive endeavors of its time worldwide. Following the completion of the sewer system, the city quickly began to dry out, resulting in a decrease in the frequency and severity of malaria outbreaks. While malaria couldn't be completely eradicated, the Romans managed to maintain better health for longer periods, leading to a gradual increase in the city's population.