Malaria incidence in Zimbabwe, 2021: A secondary data analysis

Samson Mutapure¹, Patience Dhliwayo², Tsitsi Juru¹, Gibson Mandozana¹, Gerald Shambira¹, Notion Gombe³, Addmore Chadambuka^1,&, Mufuta Tshimanga¹

 

¹Department of Global Public Health and Family Medicine, University of Zimbabwe, Harare, Zimbabwe, ²National Malaria Control Program, Ministry of Health and Child Care, Harare, Zimbabwe, ³African Field Epidemiology Network, Harare, Zimbabwe

 

 

^&Corresponding author
Addmore Chadambuka, Department of Global Public Health and Family Medicine, University of Zimbabwe, P. O. Box A178 Avondale, Harare.

 

 

 

 

The global burden of malaria was estimated at 249 million malaria cases in 2022 and there was a 16 million increase in malaria cases compared to 2019 [1] [2]. Sub-Saharan Africa continues to carry the heaviest malaria burden, accounting for about 95% of all malaria cases in 2020 [2]. Zimbabwe has made considerable progress in reducing malaria incidence compared to cases recorded a decade ago [3]. Demographic Health Information System version 2 (DHIS2) data indicated that Zimbabwe has recorded a reduction in malaria cases from 32/1000 in 2020 to 9/1000 in 2021.

 

Zimbabwe´s effort in reducing malaria transmission is achieved through case management and vector control activities [4]. Malaria case management is being implemented at both the community and facility levels to ensure easy access to care by the public, however during 2020-2021 the delivery and utilization of malaria services were disrupted due to lockdowns implemented as mitigation measures against COVID-19 [5].

 

Malaria is classified as uncomplicated or severe malaria. Uncomplicated malaria is diagnosed by the presence of clinical signs and symptoms such as headache, fever and joint pains and confirmed by a positive Rapid Diagnostic Test (RDT) or by microscopy [6,7,8]. First line treatment of uncomplicated malaria involves the use of artemether-lumefantrine (Coartemether) [7]. Primaquine is added to cases of malaria in pre-elimination districts. Severe malaria is treated by administering artesunate ether intravenously or intramuscularly [7].

 

The Ministry of Health and Child Care (MOHCC), Malaria Strategic Plan (2020-2025) targeted ten districts to have ZERO malaria transmission in the year 2021 [8]. The target had not been met and only three districts were enrolled into elimination in 2021. The last target was met in 2017 where five districts were enrolled into elimination against a target of two. For all other years from 2018 to 2021, the targets have not been met (Figure 1). We sought to establish malaria case incidence per 10 000 populations in Zimbabwe, 2021 and determine the proportion of malaria cases that were treated with first line antimalarial treatment at district level.

 

 

Study type and setting

 

We conducted a mixed methods study comprising of a descriptive study that entailed key informant interviews and a secondary data analysis of malaria data from Ministry of Health and Child Care, Zimbabwe, from DHIS2 in both control and elimination districts for the period January to December 2021. Zimbabwe adopted the sub-national malaria elimination agenda whereby districts are stratified into control and elimination based on annual parasite incidence. Districts with an Annual Parasite Index (API) of more than or equal to 5/1000 population are classified under control and those which achieve an API of less than 5/1000 population for three consecutive years may be classified under elimination. Currently, 30 districts are classified under malaria elimination and 29 districts are under malaria control. Malaria control interventions in the country include vector control using indoor residual spraying (IRS) and insecticide treated nets (ITNs), malaria case management as well as social behaviour change (SBC).

 

Data Source

 

Malaria data were obtained from the National Malaria Control Program (NMCP) DHIS2 database. The variables collected were number of malaria suspected cases, malaria positive cases, malaria cases given first-line treatment and malaria cases treated at community level. Key informant interviews were conducted to clarify issues emerging from the data set analysis. The key informants were the Data manager and M and E officer at the National malaria Control Program. Other key informants were the ten Malaria Focal persons from each of the ten provinces across the country. A standard questionnaire derived from the NMCP was used to obtain key information. The tool had questions on the number of districts moved from control to elimination in the previous year, number of districts that conducted IRS and ITNs distribution in the previous year and lastly the district with the highest incidence in in the year 2021.

 

Data Analysis

 

Malaria incidence was calculated as a ratio of the number of positive cases and the population of each district obtained from Zimbabwe population projections done in 2012. Malaria cases treated using first line medication was that proportion of cases that received first line treatment against all eligible cases. Malaria cases tested and treated by Community Health Workers (CHW) was obtained from the ratio of those cases tested and treated by CHW against all cases reported in the district. The malaria incidence was presented on maps drawn using QGIS software.

 

Ethical consideration

 

Permission to analyze data and ethical clearance was sought and obtained from the Ministry of Health and Child Care, NMCP Directorate and the Health Studies Office (HSO). Names or addresses were not used during the study. This was achieved by assigning unique identification numbers to the case investigation forms that we used during data capture, and analysis. Oral and written informed consent from key informants was obtained and the names were not collected. The interviews were conducted in their private offices. All the information concerning the study was kept private and confidentiality was maintained. Results

 

Malaria suspected cases by district, Zimbabwe, 2021

 

In 2021, 65382 people were suspected to have malaria. Of these, the majority, 50023/65382 (76.5%) were above the age of five while 15359/65382 (23.5%) were below five years. There were more suspected cases among females 35614/65382 (54.5%) as compared to males 29768/65382 (45.5%). Beitbridge District had the highest number of malaria suspected cases 13687/65382 (20.9%) whilst Umzingwane District had the least suspected cases of 631/65382 (1.0%). Among the 13687 suspected cases that were recorded in Beitbridge, 7856/13687 (57.4%) were under the age of five, while 5831/13687 (42.6%) were above five years of age.

 

Malaria incidence per 10,000 population in elimination districts, Zimbabwe, 2021

 

The incidence of malaria among the 30 elimination districts was 9.1 cases per 10 000 population. Beitbridge had the highest incidence of 48 cases per 10 000 population while Zvishavane had the lowest incidence of 0.8 cases per 10 000 population (Figure 2).

 

Malaria-positive cases who received first-line treatment by district, Zimbabwe, 2021

 

All eligible people in the following seven districts were given first line treatment: Hwedza (118/118, 100%), Mberengwa (80/80), Umzingwane (16/16), Nkayi (17/17), Mangwe (8/8), Zvishavane (11/11) and Mhondoro (253/253). However, some districts gave first line treatment to less than 80% of the eligible individuals for example Umguza (64%) and Kwekwe (79%) (Figure 3).

 

Malaria cases tested and treated by community health workers in control districts, Zimbabwe, 2021

 

The Community Health Workers (CHW) in control districts in Zimbabwe managed 75 505 malaria cases out of a total of 246 281 (30.6%) in 2021. The rest were managed at the health facilities. Among the malaria cases managed by the CHW, the greater contribution was the above 5 age-group (65 432/75 505, 86.6%) as compared to the under 5 age-group (10 073/75 505, 13.3%). Mudzi District had the highest contribution of malaria cases treated by CHW with (11315/29242) (39%). Mazowe, Hurungwe and Mhondoro reported zero cases that were treated by CHW (Figure 4).

 

Key informant interviews

 

The key informants concurred with the malaria incidence map as shown by district. The malaria cases are high along the international borders in districts such as Mudzi and Mbire. Districts failed to progress from malaria control to malaria elimination mainly due to reduced malaria control activities as people were focusing on Covid 19. Some of the districts such as Sanyati ran out of malaria medicines and commodities because of logistical challenges in distribution and redistribution of malaria commodities during the Covid 19 pandemic. There were newly recruited health care workers across the country who required mentorship on malaria case management but were unable to be trained because resources were channeled towards prevention and treatment of Covid 19. All the 30 districts under malaria control conducted IRS during the year 2021 and 19 districts provided ITNs. Among control districts, Mudzi had the highest incidence of 104/1000 in 2021.

 

Public health action done

 

Onsite malaria data verification exercises were conducted in two provinces, Manicaland (Odzi health centre) and Masvingo (Chivi District). The findings were disseminated to stakeholders at the National Malaria Elimination Review meeting and the recommendations were considered during the drafting of the review of the National Malaria Strategic Plan.

 

 

Malaria suspected cases by district, Zimbabwe, 2021

 

In 2021, 65382 people were suspected to have malaria. Of these, the majority, 50023/65382 (76.5%) were above the age of five while 15359/65382 (23.5%) were below five years. There were more suspected cases among females 35614/65382 (54.5%) as compared to males 29768/65382 (45.5%). Beitbridge District had the highest number of malaria suspected cases 13687/65382 (20.9%) whilst Umzingwane District had the least suspected cases of 631/65382 (1.0%). Among the 13687 suspected cases that were recorded in Beitbridge, 7856/13687 (57.4%) were under the age of five, while 5831/13687 (42.6%) were above five years of age.

 

Malaria incidence per 10,000 population in elimination districts, Zimbabwe, 2021

 

The incidence of malaria among the 30 elimination districts was 9.1 cases per 10 000 population. Beitbridge had the highest incidence of 48 cases per 10 000 population while Zvishavane had the lowest incidence of 0.8 cases per 10 000 population (Figure 2).

 

Malaria-positive cases who received first-line treatment by district, Zimbabwe, 2021

 

All eligible people in the following seven districts were given first line treatment: Hwedza (118/118, 100%), Mberengwa (80/80), Umzingwane (16/16), Nkayi (17/17), Mangwe (8/8), Zvishavane (11/11) and Mhondoro (253/253). However, some districts gave first line treatment to less than 80% of the eligible individuals for example Umguza (64%) and Kwekwe (79%) (Figure 3).

 

Malaria cases tested and treated by community health workers in control districts, Zimbabwe, 2021

 

The Community Health Workers (CHW) in control districts in Zimbabwe managed 75 505 malaria cases out of a total of 246 281 (30.6%) in 2021. The rest were managed at the health facilities. Among the malaria cases managed by the CHW, the greater contribution was the above 5 age-group (65 432/75 505, 86.6%) as compared to the under 5 age-group (10 073/75 505, 13.3%). Mudzi District had the highest contribution of malaria cases treated by CHW with (11315/29242) (39%). Mazowe, Hurungwe and Mhondoro reported zero cases that were treated by CHW (Figure 4).

 

Key informant interviews

 

The key informants concurred with the malaria incidence map as shown by district. The malaria cases are high along the international borders in districts such as Mudzi and Mbire. Districts failed to progress from malaria control to malaria elimination mainly due to reduced malaria control activities as people were focusing on Covid 19. Some of the districts such as Sanyati ran out of malaria medicines and commodities because of logistical challenges in distribution and redistribution of malaria commodities during the Covid 19 pandemic. There were newly recruited health care workers across the country who required mentorship on malaria case management but were unable to be trained because resources were channeled towards prevention and treatment of Covid 19. All the 30 districts under malaria control conducted IRS during the year 2021 and 19 districts provided ITNs. Among control districts, Mudzi had the highest incidence of 104/1000 in 2021.

 

Public health action done

 

Onsite malaria data verification exercises were conducted in two provinces, Manicaland (Odzi health centre) and Masvingo (Chivi District). The findings were disseminated to stakeholders at the National Malaria Elimination Review meeting and the recommendations were considered during the drafting of the review of the National Malaria Strategic Plan.

 

 

The incidence of malaria among elimination districts in Zimbabwe was 9.1 cases per 10000 population. This incidence is lower than the national incidence of 25 cases per 10000 population that was reported in 2020. Most of the malaria cases were managed at facility level and about a third were managed at the village level by CHW.

 

A reduction in malaria incidence is significant and is evidence that the public health interventions towards malaria control such as IRS and LLINs are successful. This also ensure progress towards malaria elimination in the country in line with the goal of the Ministry of Health and Child Care and will result in a reduction of the cost of health care.

 

The majority of suspected cases were above the age of five. In most cases, health workers have a higher degree of suspicion among the under-five as compared to the above five age category [9]. Our study showed contrasting results by having more suspected cases among the above five age group. This could be because adults are more likely to describe their symptoms well thereby increasing the index of suspicion of the health worker towards malaria. These results were contrary to the results of a study conducted by Makumbe et al who noted that nurses are more suspicious of malaria in the vulnerable groups who are pregnant and the under-five age group [9]. Chirebvu et al also reported similar findings in a study done in Botswana in 2016 where there were more suspected cases among the under-five age category [10-12].

 

The incidence of malaria among the elimination districts was less than the results obtained by Gunda et al. in 2017 who showed an average incidence of 19.2 per 10,000 per year in Gwanda, Zimbabwe [11]. The reductions in incidence have been attributed to the provision of Long-lasting insecticide treated nets (LLNs) and Indoor Residual Spraying (IRS) in high burden areas and improved diagnostics and effective anti-malarial treatment [12-14]. Apart from Beitbridge District, districts recorded an incidence of fewer than 10 cases per 10 000 population.

 

CHW play a pivotal role in the diagnosis and treatment of malaria cases in control districts. This is important to communities especially those that are not close to health facilities. Only nine out of the 34 control districts had village health testing and treating below 2% of the total malaria cases reported in that district. These findings are consistent with findings by Blanas et al, 2013, who revealed that some newly recruited community health workers do not understand the rapid diagnostic test algorithm and were not able to correctly test for malaria [15]. Five of the 34 districts had test rates above 30% and these were Mudzi, Mt Darwin, Rushinga, Mutoko and Chiredzi. These districts were among the top 10 high burden districts in 2020 and were sufficiently supplied with malaria rapid diagnostic test kits throughout the year [4]. The health care workers in these districts have a high index of suspicion for malaria as they regularly receive malaria case management trainings and refresher courses. The use of malaria rapid diagnostic tests by community health workers is effective for malaria case management in areas with limited functional microscopy and limited health care personnel or facilities [16].

 

Beitbridge District shares an international border with South Africa. Whilst local transmission is evident, importation of malaria across the border with South Africa is a potential source of continued malaria transmission. Vhembe District adjacent South Africa is malaria endemic [17]. Community health workers in Beitbridge have been capacitated to test and treat malaria just like their counterparts in control districts. Moreso, specific wards were also enrolled into malaria control activities similar to those in control districts such as indoor residual spraying to reduce the burden of mosquitos. Studies done by Gwitira et al. showed that there is need for interdistrict collaborative malaria interventions especially when an elimination district such as Lupane boarders a control district such as Binga [18].

 

Study limitations

 

Data on cases notified within 24 hours was not available on DHIS2. There is a possibility of under-reporting malaria cases in DHIS2 since some patients do not present to the health facilities and therefore are not reported. The DHIS2 does not capture data of malaria positive cases who receive second line treatment as treatment of first choice since there is no option to enter such data on the DHIS2 platform. Although the completeness was 100% with no missing values in all key variables, the timeliness of 92% showed late reporting by districts which may have negatively affected the quality of results as data validation may not have been done by districts before reporting.

 

 

Limitations notwithstanding, the incidence of malaria is high in the districts that share boarders with high burden malaria districts. Most suspected cases of malaria were above the age of five as compared to those under the age of five years. The proportion of malaria cases managed by community health workers in 2021 was lower than the cases managed at health facilities. Despite having low malaria cases being managed at community level, it is recommended to continuously capacitate the CHW with malaria commodities that are required for testing and treatment.

 

 

The authors declare no competing interests.

 

 

SM, PD, TJ, MT: conception and design. SM, PD, TJ, GM, AC: design data analysis, supervision. SM, PD, TJ, GM, GS, NT, AC, MT: writing, reviewing and approval of the final draft.

 

 

We would like to express our sincere gratitude to the staff of the NMCP for their support and guidance to use the DHIS2 platform during the study. We would also want to express our gratitude to the Health Studies Office Zimbabwe, for providing financial support to conduct the study.

 

 

Figure 1: Districts moved to elimination in Zimbabwe compared with targets: 2017-2021

Figure 2: Malaria incidence per 10 000 population by district, Zimbabwe, 2021

Figure 3: Malaria-positive cases who received first-line treatment by district, Zimbabwe, 2021

Figure 4: Proportion of malaria cases tested and treated by Community Health Workers in Control Districts, Zimbabwe, 2021

 

 

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