Tropical Health Matters

Solomon Afolabi has delved into the challenges for public health in 21^st Century Africa in the posting below. He is currently an Advisor to the Upper Nile Institute (UNI) of South Sudan, Kiryandongo, Uganda and an Alumnus of the Johns Hopkins Bloomberg School of Public Health and its African Public Health Network.

As we move further into the 21st century, the challenges facing public health in Africa are becoming increasingly complex and difficult to address. Despite numerous advancements in medical technology, many African nations continue to struggle with a wide range of health issues, which have been their most pressing challenges. These issues span a wide spectrum, from infectious diseases like cholera, malaria, Ebola, HIV, and more recently, coronavirus, to an escalating burden of chronic diseases. However, these health concerns are not isolated; they intersect with broader socio-economic factors such as poverty, armed conflicts, and government mismanagement. WHO in April 2023 stated that, “for all the hard-won gains that have been made over the past 75 years, more than 100 health emergencies still occur in the African Region annually, including outbreaks of cholera, yellow fever, meningitis, measles, and Ebola. These emergencies still pose a significant threat to the health, well-being, and development of African countries”

Photo: Cholera active case finding team, Kalikiliki settlement in Lusaka, Zambia (October, 2023)

The battle against infectious diseases in Africa is still ongoing. While a significant number of these diseases have been largely eradicated in other parts of the world, they continue to pose a serious threat to the health and well-being of millions of people across the continent. As earlier stated, these diseases including tuberculosis  are still major public health concerns in many African nations, and efforts to address these issues are often complicated by factors such as poverty, lack of access to healthcare, limited resources and governments not making meaningful investments.

Another major challenge facing public health in Africa is the rising incidence of non-communicable diseases (NCDs), which includes conditions such as cancer, diabetes, and cardiovascular disease, often associated with lifestyle factors such as diet, exercise, and smoking. Contrary to the traditional thought of NCDs as diseases of affluence, they are becoming increasingly prevalent in many African countries. This is partly due to changing lifestyles and the adoption of more westernized diets, as well as limited access to preventative healthcare services.

A third major challenge facing public health in Africa is the impact of environmental factors on health. Poor air quality, contaminated water, and inadequate sanitation are all major factors contributing to a range of health problems across the continent. In many cases, these environmental factors are linked to poverty and lack of access to basic resources such as clean water and sanitation facilities. Climate change is also expected to have a significant impact on public health in Africa in the coming decades, with rising temperatures and changing weather patterns likely to exacerbate existing health challenges.

Photo: Climate change projected to cause global food shortages, WHO-AFRO

Furthermore, there is the challenge of ensuring that healthcare services are accessible and affordable to all. Many African nations continue to struggle with limited resources and infrastructure when it comes to healthcare and ensuring that all individuals have access to basic healthcare services remains a significant challenge. This is compounded by factors such as corruption, political instability, and conflict, which can disrupt healthcare services and limit access to care. Despite these challenges, there are also reasons for optimism when it comes to public health in Africa. Advances in medical technology and healthcare delivery are helping to address many of these issues, and there is growing awareness of the importance of preventative healthcare measures such as vaccination and early detection. Additionally, there are many dedicated healthcare professionals and organizations working tirelessly to improve vaccine production and health outcomes across the continent.

In conclusion, the challenges facing public health in 21st century Africa are many and varied. From the ongoing battle against infectious diseases to the rising incidence of non-communicable diseases and the impact of environmental factors on health, there are many complex issues that need to be addressed. However, with continued investment and dedication, there is reason to believe that progress can be made in improving health outcomes for all Africans.

Today’s stories cover three continents including Surveillance for imported malaria in Sri Lanka, community perceptions in Colombia and Annual Fluctuations in Malaria Transmission Intensity in 5 sub-Saharan countries. In addition there is an overview of microscopy standards and an Integrated Macroeconomic Epidemiological Demographic Model to aid in planning malaria elimination. We also see how COVID-19 is disturbing Seasonal Malaria Chemoprevention activities in Burkina Faso. Read more by following the links in the sections below.

Will More of the Same Achieve Malaria Elimination?

… Results from an Integrated Macroeconomic Epidemiological Demographic Model. Historic levels of funding have reduced the global burden of malaria in recent years. Questions remain, however, as to whether scaling up interventions, in parallel with economic growth, has made malaria elimination more likely today than previously. The consequences of “trying but failing” to eliminate malaria are also uncertain. Reduced malaria exposure decreases the acquisition of semi-immunity during childhood, a necessary phase of the immunological transition that occurs on the pathway to malaria elimination. During this transitional period, the risk of malaria resurgence increases as proportionately more individuals across all age-groups are less able to manage infections by immune response alone. We developed a robust model that integrates the effects of malaria transmission, demography, and macroeconomics in the context of Plasmodium falciparum malaria within a hyperendemic environment.

The authors analyzed the potential for existing interventions, alongside economic development, to achieve malaria elimination. Simulation results indicate that a 2% increase in future economic growth will increase the US$5.1 billion cumulative economic burden of malaria in Ghana to US$7.2 billion, although increasing regional insecticide-treated net coverage rates by 25% will lower malaria reproduction numbers by just 9%, reduce population-wide morbidity by ?0.1%, and reduce prevalence from 54% to 46% by 2034. As scaling up current malaria control tools, combined with economic growth, will be insufficient to interrupt malaria transmission in Ghana, high levels of malaria control should be maintained and investment in research and development should be increased to maintain the gains of the past decade and to minimize the risk of resurgence, as transmission drops. © The American Society of Tropical Medicine and Hygiene [open-access]

Microscopy standards to harmonise methods for malaria clinical research studies

Research Malaria Microscopy Standards (ReMMS) applicable to malaria clinical research studies have been published in Malaria Journal. The paper describes the rationale for proposed standards to prepare, stain and examine blood films for malaria parasites. The standards complement the methods manual(link is external) previously published by the World Health Organization and UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR). The standards aim to promote consistency and comparability of data from microscopy performed for malaria research and hence to strengthen evidence for improvements in malaria prevention, diagnostics and treatment.

Microscopy is important in both malaria diagnosis and research. It is used to differentiate between Plasmodium species and stages and to estimate parasite density in the blood – an important determinant of the severity of disease. It is also used to monitor the effectiveness of drugs based on the rate at which parasites recrudesce or are cleared from the blood.

While rapid diagnostic tests have replaced microscopy in some contexts, microscopy remains an essential tool to support clinical diagnosis and research. The standardisation of methods allows direct comparisons from studies conducted across different points in time and location. This facilitates individual participant data meta-analyses, recognised as the gold standard approach to generate evidence for improvements in interventions and hence patient outcomes.

Estimating Annual Fluctuations in Malaria Transmission Intensity and in the Use of Malaria Control Interventions in Five Sub-Saharan African Countries

RTS,S/AS01E malaria vaccine safety, effectiveness, and impact will be assessed in pre- and post-vaccine introduction studies, comparing the occurrence of malaria cases and adverse events in vaccinated versus unvaccinated children. Because those comparisons may be confounded by potential year-to-year fluctuations in malaria transmission intensity and malaria control intervention usage, the latter should be carefully monitored to adequately adjust the analyses. This observational cross-sectional study is assessing Plasmodium falciparum parasite prevalence (PfPR) and malaria control intervention usage over nine annual surveys performed at peak parasite transmission. Plasmodium falciparum parasite prevalence was measured by microscopy and nucleic acid amplification test (quantitative PCR) in parallel in all participants, and defined as the proportion of infected participants among participants tested. Results of surveys 1 (S1) and 2 (S2), conducted in five sub-Saharan African countries, including some participating in the Malaria Vaccine Implementation Programme (MVIP), are reported herein; 4,208 and 4,199 children were, respectively, included in the analyses.

Plasmodium falciparum parasite prevalence estimated using microscopy varied between study sites in both surveys, with the lowest prevalence in Senegalese sites and the highest in Burkina Faso. In sites located in the MVIP areas (Kintampo and Kombewa), PfPR in children aged 6 months to 4 years ranged from 24.8% to 27.3%, depending on the study site and the survey. Overall, 89.5% and 86.4% of children used a bednet in S1 and S2, of whom 68.7% and 77.9% used impregnated bednets. No major difference was observed between the two surveys in terms of PfPR or use of malaria control interventions. © The American Society of Tropical Medicine and Hygiene [open-access]

Community perception of malaria in a vulnerable municipality in the Colombian Pacific

Malaria primarily affects populations living in poor socioeconomic conditions, with limited access to basic services, deteriorating environmental conditions, and barriers to accessing health services. Control programmes are designed without participation from the communities involved, ignoring local knowledge and sociopolitical and cultural dynamics surrounding their main health problems, which implies imposing decontextualized control measures that reduce coverage and the impact of interventions. The objective of this study was to determine the community perception of malaria in the municipality of Olaya Herrera in the Colombian Pacific.

A 41-question survey on knowledge, attitudes, and practices (KAP) related to malaria, the perception of actions by the Department of Health, and access to the health services network was conducted. In spite of the knowledge about malaria and the efforts of the Department of Health to prevent it, the community actions do not seem to be consistent with this knowledge, as the number of cases of malaria is still high in the area.

Use of a Plasmodium vivax genetic barcode for genomic surveillance and parasite tracking in Sri Lanka

Sri Lanka was certified as a malaria-free nation in 2016; however, imported malaria cases continue to be reported. Evidence-based information on the genetic structure/diversity of the parasite populations is useful to understand the population history, assess the trends in transmission patterns, as well as to predict threatening phenotypes that may be introduced and spread in parasite populations disrupting elimination programmes. This study used a previously developed Plasmodium vivax single nucleotide polymorphism (SNP) barcode to evaluate the population dynamics of P. vivax parasite isolates from Sri Lanka and to assess the ability of the SNP barcode for tracking the parasites to its origin.

A total of 51 P. vivax samples collected during 2005–2011, mainly from three provinces of the country, were genotyped for 40 previously identified P. vivax SNPs using a high-resolution melting (HRM), single-nucleotide barcode method. The proportion of multi-clone infections was significantly higher in isolates collected during an infection outbreak in year 2007. Plasmodium vivax parasite isolates collected during a disease outbreak in year 2007 were more genetically diverse compared to those collected from other years. In-silico analysis using the 40 SNP barcode is a useful tool to track the origin of an isolate of uncertain origin, especially to differentiate indigenous from imported cases. However, an extended barcode with more SNPs may be needed to distinguish highly clonal populations within the country.

Coronavirus rumours and regulations mar Burkina Faso’s malaria fight

By Sam Mednick, Thomson Reuters Foundation: MOAGA, Burkina Faso – Health worker Estelle Sanon would hold the 18-month-old and administer the SMC dose herself, but because of coronavirus she has to keep a distance from her patients. “If I am standing and watching the mother do it, it’s as if I’m not doing my work,” said Sanon, a community health volunteer assisting in a seasonal campaign to protect children in the West African country from the deadly mosquito-borne disease.

Burkina Faso is one of the 10 worst malaria-affected nations in the world, accounting for 3% of the estimated 405,000 malaria deaths globally in 2018, according to the World Health Organization (WHO). More than two-thirds of victims are children under five. Now there are fears malaria cases could rise in Burkina Faso as restrictions due to coronavirus slow down a mass treatment campaign and rumours over the virus causing parents to hide their children, according to health workers and aid officials.

“COVID-19 has the potential to worsen Burkina Faso’s malaria burden,” said Donald Brooks, head of the U.S. aid group Initiative: Eau, who has worked on several public health campaigns in the country.  “If preventative campaigns can’t be thoroughly carried out and if people are too scared to come to health centres … it could certainly increase the number of severe cases and the risk of poor outcomes.”

During peak malaria season, from July to November, community health workers deploy across Burkina Faso to treat children with seasonal malaria chemoprevention (SMC). This is the second year the campaign will cover the whole country with more than 50,000 volunteers going door-to-door, said Gauthier Tougri, coordinator for the country’s anti-malaria programme. Logistics were already challenging. Violence linked to jihadists and local militias has forced more than one million people to flee their homes, shuttered health clinics and made large swathes of land inaccessible. Now the coronavirus has made the task even harder, health workers said.

People in Cape Verde evolved better malaria resistance in 550 years

Yes, we are still evolving. And one of the strongest examples of recent evolution in people has been found on the Cape Verde islands in the Atlantic, where a gene variant conferring a form of malaria resistance has become more common.

Portuguese voyagers settled the uninhabited islands in 1462, bringing slaves from Africa with them. Most of the archipelago’s half a million inhabitants are descended from these peoples. Most people of West African origin have a variant in a gene called DARC that protects.

Deadly malaria and cholera outbreaks grow amongst refugees as COVID pandemic strains health systems.

Apart from the strain on health facilities during the pandemic, in some countries such as Somalia, Kenya and Sierra Leone, we are seeing that a fear of exposure to COVID-19 has prevented parents from taking their children to hospital, delaying diagnosis and treatment of malaria and increasing preventable deaths. COVID restrictions in some countries have also meant pregnant women have missed antimalarial drugs. Untreated malaria in pregnant women can increase the risk of anaemia, premature births, low birth weight and infant death. According to the World Health Organization (WHO), 80% of programs designed to fight HIV, tuberculosis and malaria have been disrupted due to the pandemic and 46% of 68 countries report experiencing disruptions in the treatment and diagnosis of malaria.

As part of the course on Social and Behavioral Foundations in Primary Health Care, Rebecca Huebsch posted in the class blog. We have shared these thoughts below.

Dafrossa Lyimo of the Ministry of Health, Tanzania presented Tanzania’s experience in preventing and controlling cholera at the 4th African Regional Immunization Technical Advisory Group (RITAG) meeting in Johannesburg, 5-8 December 2017. Those experiences are summarized below.

Cholera outbreak in Tanzania started with the index case detected in Dar es Salaam Region on 6 August 2015. The World Health Organization was notified by Ministry of Health on 15 August 2015. By 31 December 2015 the outbreak spread to 22 out of 26 regions in Tanzania Mainland. Zanzibar started reporting cholera cases on 20 September 2015 from Urban West District in Unguja Island. By December 2015, the outbreak spread to all 10 districts of Pemba and Unguja.

Cumulative cases on the Tanzania Mainland were 12 619 cases with 199 deaths (CFR 1.57%) in 2015, 11 360 cases with 172 deaths (CFR 1.5%) in 2016, and up through Nov 2017, 3 615 cases with 61 deaths (CFR 1.7%). Likewise the Cumulative cases in Zanzibar were 1 143 cases with 15 deaths (1.31%) in 2015, 3 187 cases with 53 deaths (CFR 1.66%) in 2016 and as of Nov 2017, 358 cases with 4 deaths (CFR 1.12%). The last case reported 11 July 2017

Best practices for controlling cholera in the country fall in four domains. In the area od Coordination Tanzania established a Public Health Emergency Operations Centre (PHEOC) in the Ministry of Health. To support this the Ministry appointed an Incident Manager, Deputy Incident Manager, and a PHEOC Manager for the cholera outbreak response. The National Task force Team was established with a wider composition which meeting every Friday discussing issues and giving way forward. National Rapid Response Teams were trained. these teams worked based on national response guidelines which were developed and distributed to all districts.

In the domain of Surveillance, the Ministry initiated a Daily Situation Report (SITREP) for sharing a daily cholera status in the regions and districts , on going interventions and gaps. This group conducted twice a country wide data validation/verification of the reported cases in 17 regions, which also confirmed under-reporting of cases. A Cholera reporting line list register was designed and printed in booklets and distributed to 26 regions in the Tanzania Mainland, to standardize reporting from districts and regions.

The third domain consisted of Water Sanitation and Hygiene interventions. The country distributed 21,600,000 aqua tablets of water guards in 514,285 households. Also distributed were 50 drums 45kg each of 70% High Test Hypochlorite to 83 district water authorities for bulk chlorination. Twenty hand pump boreholes were installed in hotspot villages of Mara and Mwanza regions, thereby Improving the access to clean and safe water. One hundred HACH chlorine testers were distributed for monitoring free residue chlorine in cholera reporting districts.

Social Mobilization was the fourth domain. Cholera leaflets and fliers were designed and distributed in reporting districts. Cholera messages were developed and aired through community media and mobile phone messaging. Community engagement and owning cholera interventions was undertaken using the community social networks and peer groups who focused on Hand washing, Use of treated water, and Use of toilets behaviors.

Cholera control and prevention efforts addressed various Challenges
in Tanzania. one concern was a weak surveillance system starting at the district level in several districts. Lack of reporting cholera cases, under-reporting and late reporting occurred. In some districts that had laboratory capacity, only positive cases were reported, but generally there was inadequate laboratory capacity to test and confirm Vibrio. This meant that samples had to be transported to regional laboratories (long turn around time)

A second challenge was Weak coordination at the region and District level. A third was Inadequate and poor access to WASH. this included a Limited supply of clean and safe piped water in most of districts. Thus 52% of rural population get water from unimproved sources. (Shallow wells, river, lakes and few deep wells). In urban settings, water utilities can supply water not more than 50% and still chlorination is not regularly done. there was low latrine coverage especially in rural areas. About 73% of rural population use unimproved latrines and 13% with no latrines. A fourth challenge was the Misconceptions about cholera causation and some of the interventions.

In the process of addressing these challenges several Lesson were learnt. First, a well established surveillance system helped to in the early notification of cases and quick response. Strong coordination at all level of response is important to ensure the control of outbreak is done on time. Effective social mobilization and community engagement helped in the behaviour change towards the control of cholera. Finally Adequate and good access to WASH ensured the control of spread of cholera

Tanzania has put together a comprehensive cholera prevention program based on surveillance, coordination, water & sanitation and social mobilization. While cases have reduced, Tanzania is not relenting in implementing these key interventions.

Dr Denis Marke, CH/EPI Program Manager at the Sierra Leone Ministry of Health shared his experiences from a recent natural disaster at the WHO African Regional Immunization Technical Advisory Group meeting in Johannesburg, 5-8 December 2017. Below find his observations.

Heavy rains occurred in the early hours of 14^th August 2017 that resulted in flash floods and mudslides that affected three communities (Sugar Loaf, Motomeh, and Kaningo) in the Western Area districts. The mudslides and flash floods blocked water ways and contaminated water sources in several low lying communities of Freetown, the capital city. Both mudslides and flooding destroyed houses, killing many people and displacing thousands of people. In addition, water and sewerage infrastructure were damaged.

Data collected from the emergency operations centre set up to manage the incident showed that 496 people died (168 females, 171 males of which 157 children). An additional 5,905 people were registered as displaced. The WHO assessment classified the incident as a Grade 1 emergency.

In analysis of health risks likely to affect the displaced people, cholera was ranked high on the account that there had been no confirmed Cholera outbreak since 2012. All historical outbreaks of cholera were analyzed and documented to a) Sierra Leone had had a history of 9 cholera outbreaks between 1970-2012; b) large outbreaks with case counts above 20,000 had occurred in 1994/5 and 2012; c) improved case-fatality ratios due to improvements in Health Worker skills and competencies in case management; d) almost all cholera epidemics occurred or peaked in the rainy season and e) shortening inter-epidemic periods, and thus another Cholera outbreak had been predicted since 2016.

A preventive Oral cholera vaccination concept for prevention of Cholera in Sierra Leone as part of the interventions in the emergency was mooted by WHO as the lead agency supporting the emergency response. A technical proposal for Oral Cholera vaccination was developed, presented and discussed at the Emergency Operations Centre and approved by the Ministry of Health and Sanitation. Support to implement the Oral Cholera vaccination was received from the Global Outbreaks and Alert Network, ICG, GAVI, UKaid, PIH and MSF.

Preparations for Oral Cholera vaccination broke records in terms of speedy planning and implementation. The OCV concept note was developed and approved by the MOH in 9 days. A proposal and request for OCV was approved by ICG in 72 hours. And the approved OCV doses were delivered in-country in 10 days. The national Regulatory Authority gave a waiver of vaccine registration, on the account of WHO pre-qualification and procurement through UNICEF supply division, and the OCV campaign conducted within 7 days of vaccine receipt. Notably, this was the FIRST cholera vaccination campaign EVER conducted in Sierra Leone and FIRST for that matter in an emergency.

The Objective of the OCV campaign was to provide two OCV vaccination doses to at least 95% of populations above 1 year of age living in communities affected by floods and mudslides and vulnerable populations in slums. The campaign took place in two rounds conducted on 14th – 19th September 2017 (first dose) and 5th – 10th October 2017 (second dose).

The Target Population for the Oral Cholera vaccination was all people aged >1 year resident in flood affected and slum communities of Western Area (Urban/Rural). Based on population projections for the affected communities, the estimated target was planned as 539,692 individuals.

The Oral Cholera vaccine delivery strategy was based on experiences from Oral Polio SIAs and it included four approaches: 1) House to House; 2) Schools-based temporary vaccination sites; 3) Fixed site at 22 affected Peripheral Health Units and 4) Outreach/mobile vaccination posts in camps of displaced people.

Overall the OCV Campaign reached 96.1% of the target population in the first round and 100% in the second round.  Post campaign independent monitoring documented that the overall coverage was slightly lower than was reported using the administrative reporting system. Independent monitors also documented that the main reasons for accepting vaccination were a) health information given out by health workers about the dangers of cholera, b) assurance from health workers and community leaders that the vaccine was safe. Unlike all previous Polio vaccination campaigns, radio, community social mobilizers, health workers and TV were the main source of information about the campaign.

Where non-vaccinated people were found, the major reasons were a) Poor H2H team movements and penetration; b) absence of beneficiary; c)  Acute sickness and d) unaware of vaccination dates/time. The poor team performance was attributed to the challenging terrains and clogged roads.

To verify community coverage, a post OCV Verification Survey was conducted from 21- 29 October 2017 in 140 clusters (enumeration areas). In total 2,908 Households studied and 6,987 individuals interviewed. Among people vaccinated 31.1% received only one dose and 68.6% received two doses.

In addition to oral cholera vaccination, Sierra Leone a) provided standard case definitions for cholera and trained camp commanders in the displaced populations to improve early detection of suspected cases; b) Updated and disseminated case management guidelines before conducting refresher training of case-management teams; c) Procured and prepositioned transport media for stool samples to be taken from suspected cases; d) Stock-piled and prepositioned at least 1 cholera case management kit; e) developed and disseminated IEC materials before conducting community engagement meetings with 48 Ward Councilors, 100 Market women, 120 teachers, 60 religious leaders and 40 CBO staff and f) Assured inclusion of cholera preparedness and response as a standing agenda of all EOC coordination mechanisms

This preventive effort not only kept cholera out of the area but also strengthened capacity to respond to future outbreaks and preventive campaigns. Coordination mechanisms have been established, vaccinators have been trained. Behavior change communication messages have been developed and a monitoring mechanism was tested to verify post-intervention results.  Coming out of the Ebola epidemic of a few years ago, Sierra Leone is encouraged by its new abilities to respond to emergencies and prevent outbreaks.

We acknowledge the assistance of Dr William Baguma MBABAZI, Medical Epidemiologist, EPI/WHO Sierra Leone, in the preparation of this posting.