Outbreak at a glance

From January through August 2022, more than 3.4 million suspected cases of malaria were reported in Pakistan compared with the 2.6 million suspected cases reported in 2021. Over 170 000 cases were laboratory confirmed, with the majority reported as Plasmodium vivax. A rapid upsurge in cases was observed in Balochistan and Sindh provinces after the devastating floods in mid-June 2022, together accounting for 78% of all confirmed cases. The risk is assessed as very high considering the current flood crisis affecting the capacity of the national health system.

Outbreak overview

Malaria is endemic in Pakistan. Between January and August 2022, over 3.4 million suspected cases of malaria were reported in Pakistan compared with the 2.6 million reported over the course of 2021. Over 170 000 cases were laboratory confirmed, of which 77% are due to Plasmodium vivax, and 23% due to Plasmodium falciparum, which is associated with the most severe and fatal cases.

Pakistan was hit by devastating floods in June 2022 which resulted in over 33 million people being affected, 81 districts being declared as calamity hit and the health infrastructure being badly impacted.

A rapid upsurge in reported malaria cases was observed after the floods. In Sindh province, confirmed malaria cases in August 2022 reached 69 123 compared to 19 826 cases reported in August 2021. In Balochistan province, 41 368 confirmed cases were reported in August 2022 compared to 22 032 confirmed cases in August 2021. These two provinces together account for 78% of all reported confirmed cases in Pakistan in 2022. Reports from 62 high-burden districts indicate that additional 210 715 cases were reported in September 2022, compared to 178 657 cases reported in the same districts in August 2022.

Epidemiology of Malaria

Malaria is a life-threatening disease caused by parasites that are transmitted to people through the bites of infected female Anopheles mosquitoes. Malaria transmission is also possible through blood transfusion, organ transplantation, or the sharing of needles or syringes contaminated with infected blood. Malaria can also be transmitted from mother to child before or during delivery.

There are five parasite species that cause malaria in humans, of which two of these species pose the greatest public health threat, namely Plasmodium falciparum and Plasmodium vivax. Both parasite species are reported in Pakistan, with P. vivax representing the most predominant parasite (>80%).

The first symptoms – fever, headache and chills – usually appear within 10–15 days after the infective mosquito bite and may be mild and difficult to recognize as malaria. Left untreated, malaria can progress to severe illness and death within a period of 24 hours.

Public health response

The Government of Pakistan is leading the response with support from WHO and other implementing partners. The following actions have been implemented:

• Health needs assessment was conducted in July 2022 together with other UN agencies.
• Implementation and strengthening of integrated disease surveillance and response (IDSR) activities in flood-affected districts and utilization of DHIS2 tool for daily reporting of diseases.
• Mass distribution campaign for long-lasting insecticidal nets (LLINs) was conducted in 13 outbreak and flood-hit districts by the provincial disaster management authority. An additional 600 000 LLINs have been handed over to health authorities in Sindh and Balochistan provinces for distribution to displaced populations in flood-affected districts.
• Additional teams were deployed to support vector surveillance.
• WHO provided support through coordination at multiple high-level meetings for health authorities, including enhancing liaison and coordination with provinces and partners, and the constitution of a national task force for emergency response.
• WHO has mobilized rapid diagnostic tests (RDTs) and antimalarial medicines to the provinces; about 230 000 RDTs have been provided for malaria and other diseases including acute watery diarrhea, dengue, hepatitis A & E, and chikungunya.
• WHO is supporting the development of a 6-month contingency plan for submission to the Global Fund.

WHO risk assessment

Malaria is one of the leading causes of illness and death in Pakistan. Intense transmission occurs mainly in districts located in regions bordering the Islamic Republic of Iran and Afghanistan and along the coastal belt in Sindh and Balochistan provinces. In addition, there is high population movement between Pakistan and its border countries (Afghanistan and the Islamic Republic of Iran), particularly in Khyber Pakhtunkhwa province with over 1 million Afghani refugees. Of these, nearly 800 000 refugees live in districts officially notified as calamity hit by floods, therefore the risk of international spread of the disease cannot be ruled out.

Over 33 million people have been affected by the floods and 81 districts have been declared as calamity hit. The health infrastructure was also damaged with rapid assessments indicating some 1543 health facilities and their contents have been damaged.

Given the current situation in Pakistan and limited access to health facilities and insufficient healthcare workers and essential medical supplies, there is an increased risk of serious health impacts from malaria and other ongoing outbreaks including COVID-19, acute watery diarrhoea, typhoid, measles, leishmaniasis, HIV, and polio. The risk is assessed as very high considering the current flood crisis affecting the capacity of the national health system. Many challenges to response measures surfaced when some flood-affected districts reported a doubling in incidence rates, a high P. falciparum ratio, and limited stocks of emergency medicines, insecticides and supplies accompanied with a long lead time for procurement. The lack of resources to adequately scale-up precautionary vector-control measures will certainly increase the spread of malaria and other vector-borne diseases.

WHO advice

WHO recommends malaria prevention tools and strategies including effective vector control and the use of preventive antimalarial drugs to reduce the global burden of the disease. Also, strengthening malaria surveillance is important to identify high-risk areas or populations prone to infection, enable the monitoring of changing disease patterns, and assist in designing effective public health interventions. Continued delivery of key public health messages on reducing the risk of malaria transmission among the population represents another important tool for malaria prevention and control.

Early diagnosis and treatment of malaria reduce disease severity, prevent deaths, and contribute to reducing onward malaria transmission. WHO recommends that all suspected cases of malaria be confirmed using parasite-based diagnostic testing (through either microscopy or a rapid diagnostic test). Diagnostic testing enables health providers to swiftly distinguish between malarial and non-malarial fevers, facilitating appropriate treatment.

At this stage, case management of malaria represents a critical priority to respond to the malaria situation in Pakistan, including the availability of medicines and RDTs.

Preventative measures to reduce malaria transmission also include the use of LLINs and indoor residual spraying (IRS). Vector control is a vital component of malaria control and elimination strategies as it is highly effective in preventing infection and reducing disease transmission. However, there is a limited number of LLINs available, and the distributed ones are not enough; also, the usage of LLIN by flood-affected people is not high. Additionally, available resources for IRS are extremely limited at this stage.

Since October 2021, WHO also recommends the broad use of the RTS,S/AS01 malaria vaccine among children living in regions with moderate to high P. falciparum malaria transmission. The vaccine has been shown to significantly reduce malaria, and deadly severe malaria infection, among young children.

WHO does not recommend any general travel or trade restrictions to Pakistan based on the information available for this event.

Further information

• WHO Malaria factsheet
• World malaria report 2021
• UN OCHA PAKISTAN: Monsoon Floods Situation Report No. 6 As of 16 September 2022
• Questions and answers on the RTS, S vaccine

Citable Reference: World Health Organization (17 October 2022). Disease Outbreak News; Malaria - Pakistan. Available at: https://www.who.int/emergencies/disease-outbreak-news/item/2022-DON413