Let dengue not be aided by zika and chikungunya

Although dengue has been comparatively merciful this year by claiming 497 lives as against 1,705 lives last year, it is still higher than its 269 fatalities in 2022. But zika and chikungunya reportedly infecting 11 and 67 people respectively appear as the triumvirate of evils before a nation struggling hard to tide over a critical time. Mercifully again, the latter two arthropod-borne viruses --- ZIKV and CHIKV---stopped short of reaching the high incidence of cases like dengue virus known as DENGV. Dengue cases had witnessed an unprecedented surge from 62,000 in 2022 to more than 320.000 in 2023---a five-fold increase. Aedes aegypti and Aedes albopictus serve as the main vectors of all three diseases. But in this part of the world, known for its tropical climate, DENGV has its higher prevalence with the other two still projecting a low profile. Had those two also competed with the premier febrile viral illness, it would be a health crisis almost of the order of Covid-19.

Usually, the fatalities of diseases come to the fore; what escapes notice are the socio-economic impacts they leave on health, livelihoods and economy. Two aspects here are worth noticing. First, vector-borne diseases contribute to 17 per cent of all infectious diseases worldwide mostly affecting the poorer populations. They claim 700,000 lives annually. Second, they leave prolonged after-effects even after recovery from ailments. Zika and chikungunya may be far less deadly compared to dengue but the post-illness recovery is lengthy ---taking months and years, especially in case of chikungunya. Hospitalisation for the worst cases taking long enough puts stress on poorer families' economy. In case, the patient is the bread earner, such families get devastated. Even after recovery, patients fail to get back to normal life. Vulnerable societies cannot cope with this and suffer most. An earlier study in 2015, estimated 18 countries' dengue costs at US$3.3 billion and the short-term impact of zika, the World Bank found, in Latin America and the Caribbean in 2016 was $3.5 billion.

If chikungunya proves more devastating for the survivors of the disease and their families, zika is notorious for yet other health crises and traumatic experience for pregnant mothers. It is associated with Guillain-Barre syndrome on the one hand and with microcephaly, on the other. Guillain-Barre syndrome usually begins 'with tingling and weakness' originating in feet and legs only to spread to the upper body and arms; and with its progress, muscle weakness can turn into paralysis. Microcephaly occurs to infants who are born with smaller than normal heads. If women are infected with zika during pregnancy, mothers may even miscarry, give birth to malformed or still-born babies.

So the risks from all the three diseases are clear. Since there is no vaccine nor any definite medication apart from management of the health condition, it is always better to look for effective preventive measures. One simple method is to use mosquito nets if anyone requires sleep at daytime because usually Aedes mosquitoes bite during the day. But it is wiser to eliminate the tiny winged enemy in order to avoid its bite anywhere anytime. However, the mid-November survey on Aedes larvae ---done once this year instead of three times a year--- presents a dreadful picture with higher concentration of the insects in its primary stage than even that of the rainy season last year. Clearly, the method followed to kill larvae is ineffective. So a review of the campaign to destroy larvae in their breeding grounds is urgent. Closer involvement of the community to do the job is important to obviate the unfolding of a dengue epidemic.