Mosquitoes on the rampage

A SENSE of ‘impending doom’, ‘exhaustion’, ‘fuzziness in the head’, a ‘semi-conscious state of sleep’, accompanied by fever, nausea, vomiting and excruciating body pain, is how people who have survived dengue, describe this flu-like illness, which can also be fatal.

To think that a diminutive vector — the mosquito — can wreak so much destruction on the physical and mental state of a human being is indeed overwhelming.

Of the three species spreading dengue in Pakistan, the Aedes aegypti and Aedes albopictus have been around for several years, but the hatching of the Aedes vitatus has been reported in Islamabad for the very first time.

Multiple vectors existing in multiple habitats and with diverse behaviours will pose a challenge to control strategies, explained Ijaz Ali, professor of virology at the Department of Biosciences at Islamabad’s Comsats University. Cleaning up the city, not allowing water to stand and larviciding water bodies with temephos, a chemical recommended by the WHO, and to which the mosquito has not developed resistance as yet, are integral to the fight against dengue.

It is the outbreak of malaria, especially in Sindh’s flood-affected parts, which is of more concern.

Climate change, a runway population, urbanisation and an increase in travel and transportation are further stoking the disease, and the vector has now adapted comfortably to conditions in Pakistan’s cooler regions.

First reported in 1994, it was not until 2005 when an epidemic-like situation was witnessed in Karachi; by 2010, it had spread to KP and Punjab. By 2016, Balochistan and AJK were reporting dengue cases too.

In Islamabad this year, over 2,000 cases have been reported with at least six deaths; in KP the number exceeds 6,000 with at least nine deaths; Punjab has reported over 5,000 cases, with at least eight deaths. (Lahore alone has reported over 2,000 cases.) In Sindh, since the beginning of the year, over 9,400 people tested positive (almost 7,000 in September alone); at least 38 people have reportedly died, 35 in Karachi alone.

Although this year the spike in dengue cases in urban centres can be attributed to the unprecedented rainfall — and little preparation from the government, even though it knows the monsoons are a yearly phenomenon — it is the outbreak of malaria, especially in Sindh’s flood-affected parts, which is of more concern for infectious diseases specialist Dr Sunil Dodani of Karachi’s Sindh Institute of Urology and Transplantation (SIUT).

Malaria, spread by the bite of an infective female Anopheles mosquito, has been around for years and draws less attention than dengue, although the symptoms of both are more or less the same and only a blood test can differentiate the former from the latter.

The WHO reported 241 million cases worldwide in 2020. Along with high fever, chills and sweating, symptoms can include nausea, headache, diarrhoea, fatigue, body aches, kidney failure, seizure and confusion. In severe cases, it can even lead to coma.

Dengue usually runs its seven-day course, after which, in a majority of cases, the person gets well; but if malaria remains untreated, it can prove fatal, according to Dr Khalid Qumbrani, director, public health, at the provincial health directorate of Balochistan. The death toll from malaria in the province has reached 20, he said.

The SIUT teams screening patients for both dengue and malaria, in Sindh’s flood-affected parts, especially the more remote areas where the institute’s teams are providing healthcare, said 50 per cent test positive for malaria while just 1pc test positive for dengue. Dr Dodani said the malaria outbreak continues to remain under the radar, despite being reported in huge numbers from the remote villages of Sindh.

Dr Muhammad Juman Bahoto, director general of Health Services Sindh, said up to 5,000 persons are contracting malaria every day. However, out of the total number being screened for malaria, only between 20pc to 24pc test positive. But swathes of standing water continue to pose a “grave” danger as malaria cases rise, and the “magnitude may continue to increase” he added.

Findings from Balochistan are serious too. Over the past fortnight, the positivity rate for malaria was 50pc. A little over 51,000 cases of malaria, out of 100,000 people screened, were reported from different districts, said the Balochistan doctor. Fortunately for the province, inhabitants of 26 (of its 34 districts) where malaria is endemic, are not only provided free screening, but also free treatment thanks to the Global Fund (established to defeat HIV, TB and malaria) and the WHO.

With only eight districts getting support from the Global Fund right now, the Sindh government has reached out to the latter to include all the districts, given the rise in malaria cases due to the floods.

Dr Dodani, however, predicted dengue numbers would fall in the next two weeks, as the weather gets cooler and freshwater pools dry up. But, he said, malaria will continue to rise at a frightening scale if left untreated as the stagnant water is unlikely to recede anytime soon.

Of the two common species of malaria — Plasmodium vivax and Plasmodium falciparum – the latter is more severe, according to infectious diseases specialist Dr Naseem Salahuddin at Karachi’s Indus Hospital. Already between four to five patients from interior Sindh get referred to the SIUT every day with renal failure or brain damage due to cerebral malaria, said Dr Dodani, and are “less likely to survive”.

And that is why the 650,000 flood-affected pregnant women are a big concern for the healthcare providers. According to Dr Salahuddin, if they remain undiagnosed and hence untreated for vector-borne diseases, they may develop complications and deliver prematurely or miscarry. There may also be cases where both the mother and her unborn child die.

With a huge volume of stagnant water standing in many districts of Sindh, medicated nets to ward off swarms of mosquitoes in short supply and an impending shortage of chloroquine (although Dr Bahoto said the Sindh government had over 800,000 anti-malarial drugs and the government would procure more if required), experts are mulling whether administering mass malaria prophylaxis would be an easier solution. The downside though — developing resistance to the drug — remains a formidable concern.

The writer is a Karachi-based independent journalist.