Forecasting Malaria Morbidity to 2036 Based on Geo-Climatic Factors in the Democratic Republic of Congo

A retrospective analysis of the malaria trend in Yemen over the sixteen-years, from 2006 to 2021

BACKGROUND

Malaria is one of the important diseases that threatens the global health system, especially in developing countries, including Yemen. Based on surveillance data, this analysis aimed to assess the trend of malaria in Yemen over the last sixteen years from 2006 to 2021.

METHODS

A retrospective analysis was conducted on secondary malaria data from the database from the Ministry of Public Health and Population in Yemen.

RESULTS

Of the 15,153,763 suspected cases, approximately 3,651,508 malaria cases were confirmed by both laboratory and clinical diagnoses. Plasmodium falciparum, P. vivax, mixed infections, P. malariae, and P. ovale were recorded at 1,118,117 (98.72%), 123,28 (1.10%), 1838 (0.16%), 155 (0.01%), and 30 (0.01%), respectively. Approximately 77.2% of all malaria cases were recorded in six governorates. Al Hudaydah recorded the highest number of malaria cases (1,231,294), followed by Hajjah (623,937), Taiz (450,051), Dhamar (167,399), Sa'adah (157,881), and Al-Mahweet (154,763). The overall incidence rate of malaria cases and P. falciparum, respectively, was 8.9 and 2.66 per 1,000 people. The highest mean incidence rate of malaria was recorded in Al Hudaydah, Hajjah, Al-Mahweet, Sa'adah, and Abyan, respectively, at 29.71, 19.49, 14.98, 10.62, and 10.14 per 1,000 people. Yemen reported 704 (0.02%) malaria death cases with an overall rate of case fatality of 0.03% and a mortality rate of 0.18 per 100,000 populations. The trend of case fatality decreased from 0.029% in 2006 to 0.015% in 2020, while the mortality rate per 100,000 individuals decreased from 0.3 in 2006 to 0.08 in 2021.

CONCLUSION

It currently suggests a continuous increase in the malaria burden without specifying trends or fluctuations and is becoming a public health threat and causing widespread concern. Therefore, the treatment and prevention of malaria infection are crucial for reducing mortality and complications by increasing the use of vector control tools and promoting early diagnosis and treatment.

The effects of climatic and non-climatic factors on malaria mortality at different spatial scales in western Kenya, 2008-2019

BACKGROUND

Malaria mortality is influenced by several factors including climatic and environmental factors, interventions, socioeconomic status (SES) and access to health systems. Here, we investigated the joint effects of climatic and non-climatic factors on under-five malaria mortality at different spatial scales using data from a Health and Demographic Surveillance System (HDSS) in western Kenya.

METHODS

We fitted Bayesian spatiotemporal (zero-inflated) negative binomial models to monthly mortality data aggregated at the village scale and over the catchment areas of the health facilities within the HDSS, between 2008 and 2019. First order autoregressive temporal and conditional autoregressive spatial processes were included as random effects to account for temporal and spatial variation. Remotely sensed climatic and environmental variables, bed net use, SES, travel time to health facilities, proximity from water bodies/streams and altitude were included in the models to assess their association with malaria mortality.

RESULTS

Increase in rainfall (mortality rate ratio (MRR)=1.12, 95% Bayesian credible interval (BCI): 1.04-1.20), Normalized Difference Vegetation Index (MRR=1.16, 95% BCI: 1.06-1.28), crop cover (MRR=1.17, 95% BCI: 1.11-1.24) and travel time to the hospital (MRR=1.09, 95% BCI: 1.04-1.13) were associated with increased mortality, whereas increase in bed net use (MRR=0.84, 95% BCI: 0.70-1.00), distance to the nearest streams (MRR=0.89, 95% BCI: 0.83-0.96), SES (MRR=0.95, 95% BCI: 0.91-1.00) and altitude (MRR=0.86, 95% BCI: 0.81-0.90) were associated with lower mortality. The effects of travel time and SES were no longer significant when data was aggregated at the health facility catchment level.

CONCLUSION

Despite the relatively small size of the HDSS, there was spatial variation in malaria mortality that peaked every May-June. The rapid decline in malaria mortality was associated with bed nets, and finer spatial scale analysis identified additional important variables. Time and spatially targeted control interventions may be helpful, and fine spatial scales should be considered when data are available.

Unusual clinical spectra of childhood severe malaria during malaria epidemic in eastern Uganda: a prospective study

BACKGROUND

In sub-Saharan Africa (SSA), malaria remains a public health problem despite recent reports of declining incidence. Severe malaria is a multiorgan disease with wide-ranging clinical spectra and outcomes that have been reported to vary by age, geographical location, transmission intensity over time. There are reports of recent malaria epidemics or resurgences, but few data, if any, focus on the clinical spectrum of severe malaria during epidemics. This describes the clinical spectrum and outcomes of childhood severe malaria during the disease epidemic in Eastern Uganda.

METHODS

This prospective cohort study from October 1, 2021, to September 7, 2022, was nested within the 'Malaria Epidemiological, Pathophysiological and Intervention studies in Highly Endemic Eastern Uganda' (TMA2016SF-1514-MEPIE Study) at Mbale Regional Referral Hospital, Uganda. Children aged 60 days to 12 years who at admission tested positive for malaria and fulfilled the clinical WHO criteria for surveillance of severe malaria were enrolled on the study. Follow-up was performed until day 28. Data were collected using a customized proforma on social demographic characteristics, clinical presentation, treatment, and outcomes. Laboratory analyses included complete blood counts, malaria RDT (SD BIOLINE Malaria Ag P.f/Pan, Ref. 05FK60-40-1) and blood slide, lactate, glucose, blood gases and electrolytes. In addition, urinalysis using dipsticks (Multistix^® 10 SG, SIEMENS, Ref.2300) at the bedside was done. Data were analysed using STATA V15.0. The study had prior ethical approval.

RESULTS

A total of 300 participants were recruited. The median age was 4.6 years, mean of 57.2 months and IQR of 44.5 months. Many children, 164/300 (54.7%) were under 5 years, and 171/300 (57.0%) were males. The common clinical features were prostration 236/300 (78.7%), jaundice in 205/300 (68.3%), severe malarial anaemia in 158/300 (52.7%), black water fever 158/300 (52.7%) and multiple convulsions 51/300 (17.0%), impaired consciousness 50/300(16.0%), acidosis 41/300(13.7%), respiratory distress 26/300(6.7%) and coma in 18/300(6.0%). Prolonged hospitalization was found in 56/251 (22.3%) and was associated with acidosis, P = 0.041. The overall mortality was 19/300 (6.3%). Day 28 follow-up was achieved in 247/300 (82.3%).

CONCLUSION

During the malaria epidemic in Eastern Uganda, severe malaria affected much older children and the spectrum had more of prostration, jaundice severe malarial anaemia, black water fever and multiple convulsions with less of earlier reported respiratory distress and cerebral malaria.