The rain clouds have arrived with a vengeance this year, bringing with them endless potholes, waterlogged roads and never-ending traffic jams. But, that's not it. Courtesy high humidity, the monsoon is the perfect time for water-borne diseases to thrive.
Tropical diseases, according to World Health Organization (WHO) encompass all diseases that occur solely, or principally, in the tropics. The term refers to infectious diseases that thrive in hot, humid conditions, such as malaria, leishmaniasis, schistosomiasis, onchocerciasis, lymphatic filariasis, Chagas disease, African trypanosomiasis, and dengue. Let’s look at one of the most common mosquito-borne infection in India that thrives in the monsoons – malaria.
Mosquito-Borne Infections and Malaria
For brave-hearts who think mosquitoes are just another variety of those pesky bugs, think again. Mosquitoes find this season the best time to breed and multiply – leading to various health hazards! The diseases they spread have killed more people than all the wars in history. World-wide, mosquito-spread diseases kill millions of people every year by infecting with malaria, filariasis, yellow fever, chikangunya and dengue fever.
In India, according to the National Vector Borne Disease Control Programme (NVBDCP), about 50% of malaria are due to Plasmodium falciparum. How many people exactly die of malaria in India has been a mystery. The wide range of 200 million in the frequently quoted “300–500 million cases per year” in itself reflects the lack of precision of current malaria statistics.
What Causes Malaria?
Malaria, also called the “King of Diseases” is a major public health problem in India, accounting for sizeable morbidity, mortality and economic loss. India reports around 1.5 million malaria cases annually.
Malaria is a parasitic disease that is passed from one human to another by the bite of infected Anopheles mosquitoes. In India, Plasmodium falciparum and P. vivax are the most common species causing malaria, their proportion being around 50% each. P. vivax is more prevalent in the plain areas, while P. falciparum predominates in forested and hilly areas. However, malaria caused by P. falciparum is serious; any delay in treatment may lead to consequences including death.
Diagnosis of Malaria
Since early 2010, WHO has recommended prompt parasitological confirmation by microscopy or a Rapid Diagnostic Test (RDT) for all patients suspected of having malaria, before treatment is started. According to NVBDCP and National Institute of Malaria Research (NIMR), all clinically suspected malaria cases should be investigated immediately by microscopy and/or RDT.
Microscopy
Microscopy of stained thick and thin blood smears remains the gold standard for confirmation of diagnosis of malaria. It identifies different malaria-causing parasites (P. falciparum, P. vivax, P. malariae and P. ovale), their various parasite stages, including gametocytes, and the quantification of parasite density to monitor response to treatment. It is the method of choice for the investigation of malaria treatment failures. Advantages of microscopy are high sensitivity and detection of malaria parasites at low densities. In a febrile patient, three negative malaria smears 12–24 hours apart rules out the diagnosis of malaria.
Rapid Diagnostic Test (RDT)
RDT are based on the detection of circulating parasite antigens. Such immunologic (“immunochromatographic”) tests most often use a dipstick or cassette format, and provide results in 2-15 minutes and are used in locations where microscopy results are not obtainable within 24 hours of sample collection. Also, it is recommended that all RDTs are followed-up with microscopy to confirm the results and if positive, to quantify the proportion of red blood cells that are infected.
Polymerase Chain Reaction (PCR)
PCR may be used in certain situations, such as for identifying morphologically similar species (Plasmodium malariae and P. knowlesi), for efficacy testing to distinguish new infections from relapses and recrudescences and in specific elimination and containment projects.
Serology
Serology detects antibodies against malaria parasites, and does not detect current infection but rather measures past exposure.
Routine Tests
In addition to ordering malaria specific diagnostic tests, complete blood count and a routine chemistry panel should be conducted. In case the person does have a positive malaria test, these additional tests will be useful in determining whether the patient has uncomplicated or severe manifestations of the malaria infection. Specifically, these tests can detect severe anemia, hypoglycemia, renal failure, hyperbilirubinemia, and acid-base disturbances.
Conclusion
To sum up, malaria is a major cause of death killing over 1 million people globally each year especially in tropical and sub-tropical countries. Although there are effective ways to manage malaria currently, the number of cases are is still rising due to various reasons. In such exigency, timely and precise diagnostic methods are essential for the management and control of malaria.
Agilus Diagnostics, a subsidiary of Fortis Healthcare Limited
