• Research finds disease incidence rise with higher temperature, humidity and precipitation in Thatta, Sujawal and Badin
• Suggests integration of meteorological data into healthcare surveillance system to anticipate outbreaks

KARACHI: Over 982,000 cases of infectious diseases were recorded in three coastal districts of Sindh from 2019 to 2022, with under-five diarrhoea and suspected malaria being the most prevalent, says a study that provides compelling evidence on climate variability’s significant impact on disease patterns in parts of the province.

Titled ‘Climate variability and infectious disease burden in coastal Sindh, Pakistan: A trend analysis (2019-2022)’, the study was published in International Journal of Infectious Diseases.

The research team comprised Dr Hira Tariq, a PhD scholar at the Institute of Environmental Studies (IES), Karachi University (KU) and Assistant Professor at the Aga Khan University Hospital (AKUH), who conducted the study under the supervision of Dr Aamir Alamgir and Dr Noor Fatima from IES.

They worked in collaboration with Dr Zakir Punar from the People’s Primary Health Initiative (PPHI) Sindh, and Anmol Minaz of the AKUH.

The study used an ecological time-series design to analyse facility-level surveillance data from 166 primary health centres alongside meteorological data on temperature, humidity, and precipitation from ground-based monitors and calculated incidence rates for diarrhoea, dysentery, typhoid and suspected malaria from 2019 to 2022 in Thatta, Sujawal and Badin.

According to the study, a total of 982,538 cases were recorded over the four-year period in the three districts, with under-five diarrhoea and suspected malaria being the most prevalent.

It found that disease incidence rose with higher temperature, humidity and precipitation in the studied districts.

Thatta district alone reported nearly 30,000 malaria cases in September 2022 following severe monsoon flooding. Malaria peaked 4-6 weeks after monsoon rainfall, while diarrhoea showed dual peaks in March and during monsoon months.

Monthly data showed that under-five diarrhoea exhibited two seasonal peaks: a major peak in August-September, coinciding with the monsoon season, and a smaller peak in March.

Incidence declined sharply during November and December.

Suspected malaria also peaked during the monsoon season (August-September), suggesting rainfall and humidity as major transmission drivers.

In contrast, dysentery and suspected typhoid fever showed relatively stable monthly patterns with minimal seasonal fluctuation.

According to the study, malaria cases in Pakistan rose fivefold between 2021 and 2022, making it the second-highest malaria-burdened country in the WHO Eastern Mediterranean Region.

Additionally, 40 per cent of all communicable diseases in the country are waterborne, 80pc of which are attributable to unsafe water, and only one-fifth of the population has access to clean drinking water.

The 2022 floods, which submerged nearly a third of Pakistan, had devastating public health implications in Sindh, triggering outbreaks of both gastrointestinal and vector-borne diseases.

“Despite these escalating threats, limited research has examined the specific relationship between climate variables and disease patterns in Pakistan’s coastal regions.

“This study addresses that gap by examining the incidence of waterborne (cholera, typhoid, diarrhoea) and vector-borne (malaria) diseases from 2019 to 2022 in three coastal districts of Sindh, Pakistan,” it says.

According to the study, human-induced greenhouse gas emissions have resulted in approximately a 1.2°C increase in global temperatures, triggering a cascade of environmental disruptions with direct and indirect consequences for human health.

The transmission of both malaria and dengue is influenced by temperature, rainfall, and humidity, which affect vector breeding, biting rates, and pathogen incubation periods.

Speaking about the research’s significance, Dr Amir Alamgir says it provides concrete, empirical evidence linking localised climate variability — specifically rising temperatures, monsoon rainfall, and humidity — directly to the escalating burden of infectious diseases in Pakistan’s highly vulnerable coastal zone.

“The study proves that integrating real-time weather forecasting with health surveillance can empower low-resource settings to anticipate outbreaks, allocate scarce medical supplies in advance, and protect vulnerable delta communities before the next climate disaster strikes.”

Endorsing his views, Dr Hira Tariq said that public health experts must treat weather patterns as early warning signs, tracking environmental data to stop disease outbreaks before they take root.

“When extreme heat or shifting rains alter how illnesses spread, mapping these risks in real time allows us to deploy preventative care directly to the most vulnerable neighbourhoods,” she said.

Published in Dawn, July 20th, 2026