Accuracy of verbal autopsy, clinical data and minimally invasive autopsy in the evaluation of malaria-specific mortality: an observational study

Cause-Specific Mortality among Infants in a Randomized Controlled Trial of Azithromycin Compared to Placebo for Prevention of Mortality

Although community randomized trials have found a reduction in all-cause child mortality in communities receiving mass azithromycin distribution compared with placebo, individually randomized trials have not found similar protective effects. If a direct effect of azithromycin for prevention of child mortality exists, it is likely due to reduction in infectious mortality. Here, we assessed cause-specific mortality in a large randomized controlled trial of azithromycin administered during well-infant visits in Burkina Faso for prevention of mortality. Among 32,877 enrolled infants, the most common causes of death by 6 months of age were malaria, acute respiratory infections, and diarrheal disease. We found no evidence of a difference in the distribution of cause of death by randomized treatment assignment (P = 0.42) or in any infectious-specific cause of death. The results of this analysis are consistent with no direct effect of azithromycin on infant mortality when administered during well-infant visits.

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.

Validation of malaria-attributed deaths using verbal autopsy studies: a systematic review

BACKGROUND

Malaria contributes substantially to the persistent burden of child deaths in sub-Saharan Africa. Accurate and comprehensive malaria mortality data are crucial to monitor the progress in reducing malaria incidence and mortality. Verbal Autopsy (VA) ascertains the cause of death despite its limitations leading to misclassification errors. Minimally Invasive Tissue Sampling (MITS) is being conducted in some settings as an alternative to Complete Diagnostic Autopsy (CDA). The present study examines the validity of malaria-related deaths comparing VA diagnoses with those obtained through MITS and/or CDA.

METHODS

A comprehensive literature search for original studies in English language using Ovid MEDLINE, Ovid Embase, CINAHL via EBSCO, Scopus, The Cochrane Library via Wiley, Google Scholar and searching the MITS Surveillance Alliance papers was carried out. The reference period was January 1, 1990-March 31, 2024. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were adopted.

RESULTS

Among 71 articles identified in the databases, 21 matched the eligibility criteria. Qualitative syntheses showed that malaria Cause Specific Mortality Fractions (CSMFs) across various studies ranged from 2 to 31%. Plasmodium falciparum was mostly responsible for these deaths and the most common complications were anaemia and cerebral malaria. The sensitivity and specificity of the VA validation studies ranged from 18.4% to 33% and from 86.6% to 97%, respectively, and there was a high level of misclassification for both InSilico and Expert Algorithm VA for malaria compared to MITS. The overall concordance rates between MITS and CDA diagnoses ranged from 68 to 90%, with the highest concordance seen in deaths due to infectious diseases and malignant tumours. Clinical data increased diagnostic coincidence between MITS blind to clinical data and the gold standard CDA by 11%.

CONCLUSIONS

The comprehensive review finds that MITS demonstrated better accuracy compared to VA in diagnosing malaria-attributed deaths, particularly in hospital settings. The high specificity of malaria in VA diagnosis suggests population-based estimates of the proportion of deaths due to malaria are broadly plausible.

Infectious diseases and the role of needle biopsy post-mortem

Post-mortem examinations continue to play a crucial role in understanding the epidemiology and pathogenesis of infectious diseases. However, the perceived infection risk can preclude traditional, invasive, complete diagnostic autopsy. Post-mortem examination is especially important in emerging infectious diseases with potentially unknown infection risks, but rapid acquisition of good quality tissue samples is needed as part of the scientific and public health response. Needle biopsy post-mortem is a minimally invasive, rapid, closed-body autopsy technique that was originally developed to minimise the infection risk to practitioners. Since its inception, needle biopsy post-mortem has also been used as a technique to support complete diagnostic autopsy provision in poorly resourced regions and to facilitate post-mortem examinations in communities that might have religious or cultural objections to an invasive autopsy. This Review analyses the evolution and applicability of needle biopsy post-mortem in investigating endemic and emerging infectious diseases.

Burden of child mortality from malaria in high endemic areas: Results from the CHAMPS network using minimally invasive tissue sampling

BACKGROUND

Malaria is a leading cause of childhood mortality worldwide. However, accurate estimates of malaria prevalence and causality among patients who die at the country level are lacking due to the limited specificity of diagnostic tools used to attribute etiologies. Accurate estimates are crucial for prioritizing interventions and resources aimed at reducing malaria-related mortality.

METHODS

Seven Child Health and Mortality Prevention Surveillance (CHAMPS) Network sites collected comprehensive data on stillbirths and children <5 years, using minimally invasive tissue sampling (MITS). A DeCoDe (Determination of Cause of Death) panel employed standardized protocols for assigning underlying, intermediate, and immediate causes of death, integrating sociodemographic, clinical, laboratory (including extensive microbiology, histopathology, and malaria testing), and verbal autopsy data. Analyses were conducted to ascertain the strength of evidence for cause of death (CoD), describe factors associated with malaria-related deaths, estimate malaria-specific mortality, and assess the proportion of preventable deaths.

FINDINGS

Between December 3, 2016, and December 31, 2022, 2673 deaths underwent MITS and had a CoD attributed from four CHAMPS sites with at least 1 malaria-attributed death. No malaria-attributable deaths were documented among 891 stillbirths or 924 neonatal deaths, therefore this analysis concentrates on the remaining 858 deaths among children aged 1-59 months. Malaria was in the causal chain for 42.9% (126/294) of deaths from Sierra Leone, 31.4% (96/306) in Kenya, 18.2% (36/198) in Mozambique, 6.7% (4/60) in Mali, and 0.3% (1/292) in South Africa. Compared to non-malaria related deaths, malaria-related deaths skewed towards older infants and children (p < 0.001), with 71.0% among ages 12-59 months. Malaria was the sole infecting pathogen in 184 (70.2%) of malaria-attributed deaths, whereas bacterial and viral co-infections were identified in the causal pathway in 24·0% and 12.2% of cases, respectively. Malnutrition was found at a similar level in the causal pathway of both malaria (26.7%) and non-malaria (30.7%, p = 0.256) deaths. Less than two-thirds (164/262; 62.6%) of malaria deaths had received antimalarials prior to death. Nearly all (98·9%) malaria-related deaths were deemed preventable.

INTERPRETATION

Malaria remains a significant cause of childhood mortality in the CHAMPS malaria-endemic sites. The high bacterial co-infection prevalence among malaria deaths underscores the potential benefits of antibiotics for severe malaria patients. Compared to non-malaria deaths, many of malaria-attributed deaths are preventable through accessible malaria control measures.

Altered gastrointestinal tract structure and microbiome following cerebral malaria infection

Cerebral malaria (CM) is the most severe form of malaria with the highest mortality rate and can result in life-long neurological deficits and ongoing comorbidities. Factors contributing to severity of infection and development of CM are not fully elucidated. Recent studies have indicated a key role of the gut microbiome in a range of health conditions that affect the brain, but limited microbiome research has been conducted in the context of malaria. To address this knowledge gap, the impact of CM on the gut microbiome was investigated in mice. C57BL/6J mice were infected with Plasmodium berghei ANKA (PbA) parasites and compared to non-infected controls. Microbial DNA from faecal pellets collected daily for 6-days post-infection were extracted, and microbiome comparisons conducted using 16S rRNA profiling. We identified significant differences in the composition of bacterial communities between the infected and the non-infected groups, including a higher abundance of the genera Akkermansia, Alistipes and Alloprevotella in PbA-infected mice. Furthermore, intestinal samples were collected post-cull for morphological analysis. We determined that the caecal weight was significantly lower, and the small intestine was significantly longer in PbA-infected mice than in the non-infected controls. We concluded that changes in microbial community composition were primarily driven by the infection protocol and, to a lesser extent, by the time of infection. Our findings pave the way for a new area of research and novel intervention strategies to modulate the severity of cerebral malaria disease.