Malaria: The disease of the tropics

Malaria is a disease caused by parasites of the genus Plasmodium that are transmitted to humans by the bite of infected female mosquitoes of the genus Anopheles, the so-called malaria vectors. There are five species of parasites that cause malaria in humans, although two of them – Plasmodium falciparum and Plasmodium vivax – are the most dangerous.

What are your symptoms?

Malaria is an acute febrile illness. In a non-immune individual, symptoms usually appear between 10 and 15 days after the bite of the infective mosquito. It can be difficult to recognize the malarial origin of the first symptoms (fever, headache and chills), which may be mild. If not treated in the first 24 hours, P. falciparum malaria can be aggravated, often leading to death.

Children with serious illness usually manifest one or more of the following symptoms: severe anemia, respiratory distress related to metabolic acidosis or cerebral malaria. Multiorgan involvement is also common in adults. In areas where malaria is endemic, people can acquire partial immunity, which allows the appearance of asymptomatic infections.

How is your Transmission?

Malaria is transmitted in most cases by the bite of female mosquitoes of the genus Anopheles. In the world there are more than 400 species of Anopheles, but only 30 of them are important vectors of malaria. All species that are important vectors sting between dusk and dawn. The intensity of the transmission depends on factors related to the parasite, the vector, the human host and the environment

Who is at risk?

In 2016, almost half of the world’s population was at risk of malaria. The majority of cases and deaths are recorded in sub-Saharan Africa, but the WHO regions of South-East Asia, the Eastern Mediterranean, the Western Pacific and the Americas are also affected. In 2016, 91 countries and areas experienced a continuous transmission of the disease.

According to the latest World Malaria Report, published in November 2017, in 2016 there were 216 million cases of malaria, compared to 211 million in 2015. The estimated number of deaths from malaria was 445,000, similar to that of 2015 (446,000).


Early diagnosis and treatment of malaria mitigate the incidence of the disease, reduce its deadly effects and help prevent its transmission. Confirmation of the diagnosis is made by the demonstration of malaria parasites in blood smears and in coarse blood smears. Repeated microscopic studies every 12 to 24 hours may be necessary due to the variation in the number of parasites in peripheral blood, especially in P. falciparum infection. Even, sometimes, the presence of parasites in the smears of patients who have been treated recently or who are under treatment can not be demonstrated.

There are very sensitive diagnostic methods such as nucleic acid amplification (PCR) techniques or the detection of circulating plasmodium antigens (rapid immunochromatography tests, especially useful for P. falciparum malaria). Antibodies, demonstrable by immunofluorescence or other techniques, may appear after the first week of infection and persist for years so they may indicate only a previous infection and, therefore, are not useful for the diagnosis of the current disease.

Vaccines against malaria

The RTS vaccine, S / AS01 (RTS, S) – also known as Mosquirix ™ – is an injectable vaccine that provides partial protection against malaria in young children and is being evaluated in sub-Saharan Africa as a complementary control tool that could to add (but not replace) the basic package of preventive, diagnostic and therapeutic measures recommended by the WHO.

Knowing that one of the key elements for the identification of the causative agent of malaria, is to have microscopes that have the best possible technology, in Kalstein we provide you with microscopes that will allow you to offer the better analysis. That’s why we invite you to take a look at our microscopes available HERE