Fighting malaria in Shangla District, Pakistan: insight into epidemiology, risk factors, and strategic control measures (2020–2024)

Abstract

Background

Malaria remains a significant public health challenge in District Shangla, Pakistan, exacerbated by ecological diversity, seasonal transmission, and limited health infrastructure. This 5-year epidemiological study aimed to assess malaria trends, species distribution, risk factors, and intervention outcomes from 2020 to 2024.

Methods

A retrospective analysis was performed on 130,401 laboratory-confirmed malaria cases identified from 572,696 febrile individuals screened between 2020 and 2024. Data were collected through district health surveillance systems and field-based reports. Epidemiological indicators, including Annual Parasite Incidence (API), Test Positivity Rate (TPR), and Annual Blood Examination Rate (ABER), were analyzed alongside demographic, diagnostic, seasonal, and behavioral data. The impacts of interventions were assessed by comparing trends before and after the interventions.

Results

Malaria incidence increased sharply from 2020 to 2023, with API rising from 2 to 61 per 1000 populations, TPR from 3 to 32%, and ABER from 5 to 19%. In 2024, these indicators declined (API: 46/1000; TPR: 27%; ABER: 18%) following targeted interventions. Plasmodium vivax comprised 95% of cases, followed by Plasmodium falciparum (4.6%) and mixed infections (0.4%). Only 18% of cases were microscopy-confirmed; the remainder relied on rapid diagnostic tests (RDTs). Adults ≥ 15 years accounted for 67% of cases, with a male predominance (54%). Seasonal peaks varied: P. vivax peaked in July–August, while P. falciparum peaked in October–November. Risk factors included poor treatment adherence (only 14% completed primaquine regimens), absence of G6PD screening, misinformation, reliance on informal providers, and population mobility.

Discussion

The rise in malaria burden reflects climate-sensitive transmission, diagnostic gaps, and inadequate treatment adherence. The decline in 2024 corresponds to coordinated responses, including deploying 78 diagnostic and treatment centers, expanded IRS, LLIN distribution, and health education campaigns. However, persistent gaps in vector surveillance, diagnostic accuracy, primaquine adherence, and health worker training hinder progress.

Conclusion

Malaria control in Shangla requires an integrated, climate-adaptive elimination strategy. Priorities include enhanced vector control, improved diagnostic access, universal G6PD testing, community-based health education, and use of short-course antimalarial regimens with full primaquine adherence to sustain control and advance toward elimination.

Background

Malaria remains a significant global public health challenge, particularly in tropical and subtropical regions, with an estimated 249 million cases and 608,000 deaths reported globally in 2022, the majority of which occurred in sub-Saharan Africa [1]. Underage children (below 5 years) and pregnant women continue to bear the highest burden of the disease. Despite progress in prevention and treatment, emerging drug-resistant Plasmodium falciparum strains and insecticide-resistant mosquito vectors threaten malaria control efforts [2]. Climate change further exacerbates the risk by expanding the geographic range of Anopheles mosquitoes [3].

In Pakistan, malaria is among the top 5 diseases by burden, in rural and peri-urban regions where climatic and socioeconomic conditions favor transmission. It is reported that 3.5 million suspected cases and over 400,000 confirmed cases occurred in [4]. The current study area (district) has one of the highest incidences of malaria reported. Malaria in Pakistan is unevenly distributed, with the highest incidence reported in Baluchistan, Khyber Pakhtunkhwa (KP), Sindh, and the Federally Administered Tribal Areas (FATA). Baluchistan reported the highest malaria burden, with an API of approximately 70.3 per 1000 population, reflecting widespread transmission and limited access to preventive services [5]. Sindh province, which accounted for nearly 49.4% of the national malaria cases, had a high API, though lower than Baluchistan, due to persistent transmission in riverine and flood-prone districts [6]. In Khyber Pakhtunkhwa (KP), including the merged tribal areas (formerly FATA), the API ranged between 11.0 and 12.9 per 1000, placing it among the moderately high transmission zones [1]. These values underscore the urgent need for region-specific interventions under Pakistan’s National Malaria Strategic Plan 2021–2035 [7]. The districts bordering Afghanistan and Iran account for 37% of cases and annual parasite incidence (API) exceeding 4.5 per 1000 population [8]. Plasmodium vivax dominates (79.1% of cases), though Plasmodium falciparum prevalence has risen to 16.3%, particularly in regions where P. vivax was historically endemic [9]. Recent estimates indicate a national pooled prevalence of 23.3%, with extreme variability across districts—ranging from 1.7% in Larkana to 99.8% in Karachi. Malaria transmission in Pakistan follows seasonal patterns, peaking in the post-monsoon period (July–November) due to increased mosquito breeding sites. The primary vector, Anopheles stephensi, thrives in irrigated agricultural areas and urban water storage containers, facilitating transmission in both rural and urban settings [10]. Recent climate shifts, including erratic rainfall and rising temperatures, have expanded malaria’s geographic range, with previously low-risk districts now reporting outbreaks [11]. Socioeconomic factors, such as low-income households with limited access to bed nets and healthcare services [4], and behavioral factors, such as outdoor nighttime activities and delays in seeking treatment [12], further exacerbate disease transmission.

Pakistan has implemented multifaceted control strategies, achieving a 45% reduction in malaria cases between 2015 and 2020 through the expanded use of rapid diagnostic tests (RDTs), artemisinin-based combination therapy (ACT), and long-lasting insecticidal nets (LLINs) [13]. Nonetheless, significant challenges remain, including climate-driven increases in transmission—malaria cases are projected to rise by 0.8–3.5% by the 2060 s under high-emission scenarios [9], and gaps in surveillance, particularly in regions like Gilgit-Baltistan and Azad Jammu and Kashmir [10].

In districts such as Shangla, assessing the malaria burden is essential for protecting public health and improving socioeconomic conditions. The region’s population primarily depends on daily wages, making households particularly vulnerable during outbreaks. In endemic areas, malaria transmission seasons can severely impact entire families, with multiple members—sometimes all—becoming ill and unable to work. This not only endangers health but also disrupts livelihoods.

The present study investigated the underlying causes of the recent surge in malaria cases despite routine control interventions. It aims to assess current epidemiological trends, identify key risk factors contributing to transmission, and evaluate the effectiveness of existing control strategies in order to propose more targeted and sustainable solutions.

Methods

Study design, area, and period

This cross-sectional, epidemiological sero-surveillance study was conducted in the Shangla part of Khyber Pakhtunkhwa (KPK), Pakistan. The total population of the area is about 891,252, with approximately 524,480 in the endemic area of four tehsils, like Besham, Chakisar, Martung, and Puran. This study was done from January 2020 to December 2024.

Investigation of the socio-economic status of the study area

The economy of the study area mainly relies on subsistence farming and labour migration. Widespread poverty, limited healthcare access, and poor infrastructure increase the region’s vulnerability to infectious disease spread.

Sample selection and risk factors

A total of 78 health facilities were selected for the study; five offered microscopy-based malaria diagnosis, while the remaining facilities relied on rapid diagnostic tests (RDTs) in malaria-endemic areas. Epidemiological data were obtained from each designated malaria health facility. The data were categorized by gender, age group, pregnancy status, Plasmodium species, diagnostic method, and associated risk factors.

Microscopy services for malaria diagnosis

Microscopy remains a gold standard for malaria diagnosis in many resource-limited settings. In Shangla district, only five public health facilities are equipped with microscopy services for malaria diagnosis. As per established WHO guidelines, standard procedures for preparing thick and thin blood smears, staining with Giemsa, and microscopic examination are followed for the detection and identification of Plasmodium species. The identification of Plasmodium species is based on morphological characteristics and staining properties. Detailed protocols for these methods are well-documented in WHO manuals and other authoritative sources [4, 14, 15].

Rapid diagnostic tests

Rapid diagnostic tests (RDTs) are critical in malaria detection, especially in remote settings where microscopy services are unavailable. In this study, SD BIOLINE Malaria Ag P.f/P.v test kits (Abbott) were used, which are widely recognized for their ease of use, minimal training requirements, and quick results [16]. Detailed protocols and performance evaluations are available in the WHO and manufacturer documentation [17, 18]. These tests have been widely adopted in field epidemiology due to their portability, reliability, and effectiveness in enabling rapid treatment decisions and strengthening disease surveillance.

Questionnaire

A structured questionnaire was administered to 1000 laboratory-confirmed malaria-positive patients in identified hotspot areas as part of an epidemiological survey designed to assess trends and identify consistent increases in case burden (Figs. 1, 2, 3, 4, 5).

Fig. 1.

This structured questionnaire was used to collect detailed epidemiological data from 1000 laboratory-confirmed malaria-positive patients in hotspot areas of District Shangla. It includes demographic, environmental, behavioral, and treatment-related variables to assess trends, risk factors, and patterns in malaria transmission

Fig. 2.

Yearly trends in key malaria surveillance indicators in Shangla District (2020–2024). The graph illustrates variations in (ABER), Test Positivity Rate (TPR), (API), and P. falciparum ratio. A marked increase in all indicators peaked in 2023, followed by a decline in 2024

Fig. 3.

Seasonal trends in malaria species distribution over 3 years in Shangla District

Fig. 4.

Five-year trend of malaria cases in Shangla District (2020–2024). The graph illustrates a steady increase in all types of malaria cases—Plasmodium vivax, P. falciparum, and mixed infections—reaching a peak in 2023, followed by a notable decline in 2024, likely reflecting the impact of intensified intervention and treatment strategies

Fig. 5.

Microscopic view of Plasmodium spp. parasites in stained blood smears

Data analysis

Data from the designated health facilities were collected during routine monitoring and recorded in the maintained FM-2 and FM-3 registers. FM-2 documents outpatient consultations, while FM-3 captures details of disease-specific cases, including confirmed malaria diagnoses, treatments provided, and follow-up outcomes. These standardized national formats ensure consistency and accuracy in health data reporting across both public and private sector facilities [5].

Graph Pad Prism version 9.0.2 was used for data analysis. For continuous variables, means and standard deviations (SD) were calculated, while frequencies and percentages were reported for categorical variables. The chi-squared (χ²) test was applied to assess associations between categorical variables, with a p-value ≤ 0.05 considered statistically significant (Tables 1, 2).

Table 1.

Tabulated values of Annual trends of ABER, TPR, API, and P. Falciparum ratio

Years	Annual blood examination rate (ABER) (%)	Test positivity rate (TPR) (%)	Annual parasite incidence (API) (%)	Pf ratio (%)
2020	5	3	2	2
2021	7	9	6	4
2022	13	22	28	7
2023	19	32	61	6
2024	18	27	46	3

Table 2.

Treatment history and primaquine adherence among 1000 confirmed P. vivax malaria cases in Shangla District

Total cases	1000	Only chloroquine no primaquine	Incomplete dose of primaquine	Completed primaquine with improper dosage	Complete dosage of primaquine and chloroquine
New	135	–	–	–	–
Previously reported	865	360 (41.6%)	221 (25.5%)	164 (18.95%)	120 (13.87%)

Results

Epidemiological surveillance of malaria in Shangla

From 2020 to 2024, a total of 572,696 individuals were screened for malaria, of which 129,401 (22.6%) were confirmed positive. Of these, 23,239 cases (18%) were diagnosed using microscopy, while 107,162 cases (82%) were confirmed through rapid diagnostic tests (RDTs). Plasmodium vivax was the predominant species, accounting for 123,646 cases (95%), followed by P. falciparum (6154 cases; 4.6%) and mixed infections (601 cases; 0.4%).

Regarding gender distribution, 70,641 cases (54.18%) were reported in males and 59,760 cases (45.82%) in females, including 1034 pregnant women (1.7%). Age-wise, 8239 cases (6%) occurred in children aged 0–4 years, 35,313 cases (27%) in the 5–14 age group, and the majority, 86,849 cases (67%), were in individuals aged 15 years and older.

Chi-square analysis showed that the distribution of malaria species over the 5-year period was statistically significant (χ² = 724.4, p < 0.001). A notably higher prevalence was also seen in individuals over 15 years old (χ² = 1193, p < 0.0001) and among males compared to females (χ² = 385.8, p = 0.0001). These results are summarized in Tables 3 and 4.

Table 3.

Annual malaria screening and diagnostic outcomes in District Shangla (2020–2024)

Years	RDTs	Microscopy	Total positive	P. vivax	P. falciparum	Mixed cases
2020	1441	178	1621	1586	33	02
2021	5395	301	5697	5462	232	03
2022	23,882	1575	25,457	23,747	1576	134
2023	45,024	9927	55,330	51,890	3036	404
2024	31,420	11,258	42,296	40,961	1277	62
Total	107,162	23,239	130,401	123,646	6154	601

Table 4.

Demographic characteristics of population, Gender-, age-, and pregnancy-specific distribution of malaria cases in Shangla District from 2020 to 2024

Years	Male	Female	Pregnant women	0–4 years	5–14 years	15 + years
2020	1089	533	8	13	124	1505
2021	3365	2332	133	446	1360	3891
2022	13,840	11,612	192	2038	6598	16,819
2023	29,491	25,841	467	4061	15,615	35,654
2024	22,856	19,442	234	1681	11,616	28,999
Total	70,641 (54.%)	59,760 (46%)	1034 (1.7%)	8239 (6.3%)	35,313 (27%)	86,849 (66.6%)

This table summarizes key malaria surveillance indicators and trends over a 5-year period.

Epidemiological survey

An additional epidemiological survey using structured questionnaires was conducted at the start of 2024, in malaria hotspot health facilities, to gather information not typically captured during routine data collection. The survey included 1000 confirmed P. vivax cases. Among these, 865 individuals (86.5%) reported a previous history of malaria infection, while 135 cases (13.5%) were newly diagnosed. Among the 865 patients with prior infections, 360 patients (41.6%) had received only chloroquine and avoided primaquine, instead resorting to non-recommended antimalarial treatments, 221 patients (25.5%) initiated primaquine therapy but failed to complete the full course, and 164 individuals (18.95%) completed treatment but received incorrect dosages. Only 120 individuals (13.87%) adhered to the full recommended regimen of both primaquine and chloroquine; however, they experienced reinfection, likely due to new transmission events rather than relapse.

Seasonal trends & year-wise burden

Here is the seasonal trends graph, which shows the peaks of Plasmodium species. Plasmodium vivax cases peaked consistently during the mid-monsoon months of July and August. Plasmodium falciparum and mixed infections showed delayed peaks in the post-monsoon period, primarily in October and November, reflecting differences in vector ecology and parasite biology.

The number of confirmed cases increased significantly each year. In 2020, 48,836 individuals were screened, and 1621 (3.3%) tested positive. In 2021, 66,678 were screened, with 5697 (8.5%) confirmed cases. In 2022, 118,249 individuals were screened, and 25,457 (21.5%) tested positive.

The upward trend continued in 2023, with 175,410 screenings and 55,330 (31.5%) confirmed cases, and 163,523 individuals were screened, with 42,296 (25.9%) confirmed positive for malaria in 2024.

Plasmodium species distribution (P. vivax, P. falciparum)

The table presents a 5-year overview (2020–2024) of malaria surveillance in Shangla District, Pakistan, including total screenings, diagnostic methods used (RDTs and microscopy), and species-specific breakdown of confirmed positive cases. A total of 572,696 individuals were screened, with 130,401 (23%) testing positive for malaria. Malaria cases rose significantly between 2020 and 2023, peaking at 55,330 cases 2023. A notable decline occurred in 2024, with 42,296 cases, potentially indicating the impact of primaquine mass administrations (Tables 5, 6).

Table 5.

Year-wise distribution of malaria diagnostic methods used in Shangla District

Years	Total Screenings	RDTs	Microscopy
2020	48,836	1441	178
2021	66,678	5395	301
2022	118,249	99,491	18,758
2023	175,410	45,024	9902
2024	163,523	31,295	11,233
Total	572,696	107,037	23,189

Table 6.

Stock received from provincial government 2024

Name of items	Total stock received
Fendona 10% SC	167 Letters
Icon (2.5 E.C)	88 letters
Temephose liq 500 EC	50 kg
LLINs	11,250
Thermal fogger hand held	2
Spray pumps	14
PPEs	24 KITS

Risk factors

The table below shows the gender- and age-wise distribution of confirmed malaria cases in Shangla District over a 5-year period (2020–2024), with special emphasis on vulnerable populations, including pregnant women and children. Among females, 1.7% occurred in pregnant women, a high-risk group for malaria complications. Children aged 0–4 years represented 6.3% of total cases. The 15+ age group consistently showed the highest burden, indicating occupational or behavioral exposure risks.

Microscopy services

In District Shangla, microscopy-based malaria diagnosis was conducted at five key public health facilities, accounting for 18% of the total confirmed cases. Microscopy confirmed infections of P. falciparum, P. vivax, and mixed species, while also providing detailed demographic insights. This technique enabled accurate identification of species, as well as gender- and age-specific distributions, supporting targeted treatment and surveillance efforts.

Rapid diagnostic tests

In the study area, a total of 67 health facilities—including both public and private centers—utilized Rapid Diagnostic Tests (RDTs) as the primary method for malaria screening. These facilities accounted for the diagnosis of approximately 82% of all confirmed malaria cases from 2020 to 2024. RDTs proved essential in enhancing early detection and case management, particularly in remote or resource-limited settings where microscopy services are unavailable. Their ease of use, rapid turnaround time (15–30 min), and minimal training requirements enabled widespread deployment, contributing significantly to the timely diagnosis and treatment of P. vivax, P. falciparum, and mixed infections across diverse populations.

Malaria control strategies

The National Malaria Control Programme (NMCP) provides national guidelines and technical support. In 2023, the UNICEF provided 11,250 LLINS, which were distributed in the hotspot areas. The provincial government provides technical and logistic support to the district team for anti-vectors activities, awareness campaigns, health education programmes, also in collaboration with The Indus Hospital Network backed by Global funds, support in Indoor Residual Spraying (IRS) in tehsil Puran, also their district team established 78 malaria free diagnostic and treatment centers across the endemic areas. The district administration involved the line departments in multi-tasking approaches to control the VBDs in the district.

Discussion

This 5-year surveillance and survey-based investigation revealed a sustained rise in P. vivax malaria burden in District Shangla, Pakistan, from 2020 to 2023. This increase was driven by a convergence of socio-economic, behavioural, and systemic health factors. The Annual Blood Examination Rate (ABER) rose from 5 to 19%, reflecting expanded surveillance, while the Test Positivity Rate (TPR) increased from 3 to 32%, and the Annual Parasite Incidence (API) escalated from 2 to 61 per 1000 populations, indicating high levels of transmission. In 2024, following targeted public health interventions, these indicators declined—ABER to 18%, TPR to 27%, and API to 46 per 1000—suggesting a measurable impact of the response.

The economic consequences of the malaria surge were substantial, with an estimated loss of PKR 550 million in 2023 alone due to direct medical costs, transportation, and lost income. Post-COVID changes in health-seeking behavior further complicated control efforts, as many patients bypassed formal health systems in favor of informal or unqualified practitioners. Misinformation surrounding primaquine—a key component of the radical cure for P. vivax—led to widespread treatment non-adherence and high relapse rates.

A supplementary epidemiological survey in early 2024 revealed that only 14% of previously infected individuals had completed the full course of primaquine and chloroquine. Over 86% either never initiated treatment, received sub-therapeutic doses, or discontinued prematurely. Reluctance was largely due to the treatment's duration, lack of awareness, and misinformation propagated by unregulated providers. Although G6PD testing infrastructure was not directly identified as a barrier in this study, its general absence in endemic regions remains a recognized constraint for primaquine prescription.

In response, WHO-trained personnel and local health authorities introduced targeted interventions: training healthcare workers on accurate primaquine dosing, patient counseling, and adherence monitoring; expanding diagnostic services; and enhancing community awareness. These actions coincided with a reduction in API and TPR in 2024, indicating the positive impact of coordinated, multisectoral efforts.

Throughout the study, P. vivax accounted for 95% of confirmed cases, consistent with its dominance in the region and its ability to relapse due to dormant hypnozoites. Plasmodium falciparum remained comparatively rare, peaking at 7% in 2022 and declining to 3% in 2024. These trends align with regional patterns in South Asia [1, 19].

Shangla’s north–south ecological gradient was key in shaping transmission patterns. The warmer southern lowlands support prolonged Anopheles breeding and transmission from May to November, whereas high-altitude northern areas experience seasonal interruption due to sub-15 °C winter temperatures. Nonetheless, malaria transmission persists through two main mechanisms: (1) relapses from P. vivax hypnozoites during low-transmission seasons and (2) reintroduction via returning migrant labourers from endemic regions, such as Punjab and Sindh [20, 21].

Distinct seasonal peaks were observed: P. vivax transmission peaked in July–August, coinciding with early monsoon rains and rapid development in vectors like Anopheles culicifacies, while P. falciparum peaked later in October–November and was linked to post-monsoon breeding of Anopheles stephensi and its higher thermal development threshold. These observations align with other South Asian reports [19, 22].

Diagnostic trends revealed widespread reliance on rapid diagnostic tests (RDTs), which accounted for 82% of confirmed cases, while microscopy confirmed only 18%. Although RDTs have improved access in remote settings, limited microscopy use may hinder species differentiation and detection of low-parasitemia cases [23]. Furthermore, without routine confirmatory testing or external quality assurance, diagnostic reliability remains a concern.

In 2024, the reduction in malaria cases coincided with a coordinated response involving WHO-trained teams, the Indus Hospital Network, and the Global Fund. Key interventions included the establishment of 78 diagnostic and treatment centers, mass distribution of long-lasting insecticidal nets (LLINs), targeted indoor residual spraying (IRS), and community-level awareness campaigns. These efforts, alongside strengthened primaquine adherence monitoring, likely contributed to the observed decline in transmission.

Despite progress, critical challenges persist. Continued reliance on RDTs without confirmatory microscopy, the influence of informal providers, low community health literacy, and stock limitations of IRS chemicals and PPEs pose significant threats to sustained control. Misinformation about primaquine continues to undermine adherence, while the absence of G6PD testing infrastructure may constrain safe prescription practices. These systemic barriers are consistent with findings from other endemic regions [1, 24].

This study had several limitations. It relied primarily on passive facility-based surveillance, potentially underestimating asymptomatic or unreported cases. The 2024 behavioural survey, while informative, focused only on confirmed P. vivax cases and may not capture broader community practices. Additionally, molecular diagnostics (PCR) were not uniformly applied, limiting confirmation in suspected mixed infections.

Overall, this investigation underscores the multifactorial drivers of malaria resurgence in highland South Asia, particularly in ecologically diverse and resource-limited regions like Shangla. Sustainable control will require continued investment in surveillance, diagnostic infrastructure, community engagement, and targeted treatment strategies. The Shangla experience illustrates both the vulnerabilities and opportunities inherent in malaria control and may serve as a model for context-specific P. vivax elimination efforts.

Conclusion

Shangla District in Khyber Pakhtunkhwa remains a high-burden malaria zone, with P. vivax responsible for the vast majority of (95%) of confirmed cases between 2020 and 2024, followed by P. falciparum (4.6%) and mixed infections (0.4%). The persistent transmission is driven by multiple, interconnected factors: incomplete adherence to primaquine treatment (leading to a 74.5% relapse rate), inadequate G6PD deficiency screening, climate warming, and frequent population movement, especially labor migration from endemic regions. Environmental changes, such as rising temperatures and erratic rainfall, have expanded mosquito habitats into higher altitudes, further complicating control efforts.

Although a significant decline in malaria cases was observed in 2024 following targeted interventions, including improved primaquine compliance, intensified vector control, and public health education, significant challenges remain. These include limited diagnostic capacity, insufficient coverage of long-lasting insecticidal nets, and behavioral barriers to treatment adherence.

Sustainable malaria elimination in Shangla will require integrated, locally adapted strategies that address clinical, environmental, and socioeconomic determinants. Priority actions should include expanding G6PD testing, strengthening vector surveillance, promoting radical cure adherence, scaling up community-based education, and a short-duration treatment anti-malarial drug is the key need for preventing and eradicating malaria. This multifaceted approach is essential to effectively reduce malaria transmission and address the unique vulnerabilities of mountainous regions like the Shangla region.

Author contributions

The authors thank the District Health Office Shangla, malaria field staff Shangla, facilities in charge, WHO country technical officers, the TIH district Shangla staff, and the Department of Infectomics & Molecular Pathogenesis at Cinvestav Mexico for their support. Special thanks go to the patients who voluntarily participated in the study.

Funding

The Global Fund partly supported this study to fight AIDS, Tuberculosis, and Malaria, and the Indus Hospital Network as part of a malaria control initiative. The District Health Department of Shangla provided additional support. The funding bodies had no role in study design, data collection, analysis, interpretation, or manuscript writing.

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethics approval and consent to participate

Not applicable.

Competing interests

The authors declare no competing interests.