The first quarter of 2019 saw an increased burden of dengue fever in Mumbai compared to last year, official figures show. Yet there may be other causes for concern when it comes to infectious diseases in the metro.
India’s largest city and the state capital of Maharashtra reported 44 cases of dengue in the January-March period this year, compared to nineteen cases reported during the same period in 2018. City officials say the increase poses no concern for alarm, as it is likely the result of changed weather patterns. However, private doctors tell a different story. This is not necessarily concerning dengue, but other infections – in particular, H1N1.
“Dengue is the fastest-growing viral infection transmitted by mosquitoes – ahead even of conditions such as malaria. H1N1, by contrast, is a much more recent phenomenon…[gaining] prominence in 2019 because of a global pandemic”
To compare the two diseases, dengue is a mosquito-borne disease. Its worldwide incidence increased thirtyfold in a fifty-year period, its prevalence shifting from just a handful of countries to becoming endemic in 128 nations including India. Dengue is considered endemic across all 35 states and union territories (UTs).
The rise is severe enough that, according to the World Health Organisation (WHO), dengue is the fastest-growing viral infection transmitted by mosquitoes – ahead even of conditions such as malaria.
H1N1, by contrast, is a much more recent phenomenon. A strain of influenza, H1N1 gained prominence in 2009 because of a global pandemic declared by the WHO, with a number of humans becoming infected with the disease originating in cases of flu in pigs (swine influenza). As many as 284,000 people died in the 2009-10 pandemic (though official estimates vary). Then-WHO Director General Dr Margaret Chan declared the pandemic over in August 2010.
“A global trend of rising temperatures, leading to expanded mosquito populations including in areas where they may not necessarily have bred before”
Both dengue and swine flu are public health issues of significant concern in India. Many cities, states and UTs are reporting increased incidences of dengue. Across Maharashtra, dengue cases rose by 41 percent between 2017 and 2018. The state accounts for one third of dengue deaths in India.
This can be attributed – at least in part – to a global trend of rising temperatures, leading to expanded mosquito populations including in areas where they may not necessarily have bred before. As such, dengue vector species are enjoying greater prevalence. Two such species – Aedes aegypti and Aedes albopictus – have seen their breeding capacity increase by three and six percent respectively since 1990.
H1N1, meanwhile, has been a public health menace for a number of years. It regularly makes rounds during India’s flu season. Last year, multiple states displayed prevalence of swine flu with Maharashtra bearing the brunt.
“Maharashtra can be considered a H1N1 hotspot in India given its high burden of the disease. Dengue, meanwhile, is also making its rounds”
Let us return now to Mumbai. As mentioned above, Maharashtra can be considered a H1N1 hotspot in India given its high burden of the disease. Dengue, meanwhile, is also making its rounds – but officials say there is slim cause for alarm. While there is perhaps some concern in the fact that dengue is rearing its head in advance of the monsoon season, officials say that few patients required hospitalisation for the disease and most were treated in outpatient departments.
“If patients keep an eye on the symptoms and approach doctors for quick diagnosis, we will be able to control the cases,” said Dr Om Srivastava, infectious diseases department head at Jaslok Hospital. They noted that just one percent of reported cases necessitated treatment in intensive care units (ICUs).
Yet, when it comes to H1N1, there is ample cause for concern according to some medicos. Officials report 121 cases of the disease in the January-March period. In facilities and clinics, doctors report a spike in H1N1 cases. Statewide, Maharashtra reported almost 1,100 cases and 73 deaths in the January-March period.
“Viral infections must be monitored vigilantly and addressed multisectorally, to mitigate the risk of person-to-person transmission”
This lends itself to concern as similar patterns have been observed in other states. In Dehradun, for example, the number of cases reported in a single hospital matched what officials reported for the entire city.
Lessons can – and must – be taken from the dengue and H1N1 issues in Mumbai. Viral infections must be monitored vigilantly and addressed multisectorally, to mitigate the risk of person-to-person transmission. The impetus is upon officials, doctors and patients to cooperate and ensure that diseases are tracked, treated and addressed. There is no reason to suggest that this is not occurring in Mumbai, but when there are disparities between what officials say and what doctors say on the ground, this inevitably will raise some eyebrows.