CHANGING TRENDS IN THE DIAGNOSIS OF MALARIA AND TYPHOID FEVER

Malaria In tropical Africa, fever is commonly associated with malaria that was known variously as Roman fever,   marsh fever(Rocco 2003),  and whose name was derived from the Italian ‘Mal=bad, Aria=air.’(Prakash et al. 2013).    Malaria is caused by five species of the plasmodium parasite: P. falciparum, P. vivax, P.ovale, P. malariae and P. knowlesi all of which are transmitted by the female anopheles mosquito, which is the vector of the parasite. Over 2.4 billion people are at risk of P. falciparum infection, which results in about 300 to  500 million clinical episodes and 1million deaths annually (Bousema & Drakeley 2011). While about 2.9 billion persons are at risk for P. vivax infection with up to 300 million clinical episodes per year(Bousema & Drakeley 2011). A vast proportion of malaria morbidity occurs in sub-Saharan Africa, (SSA). However, there is substantial evidence that the intensity of malaria transmission in Africa is declining (Snow et al. 2012, Graz et al. 2011), and rapid malaria parasitemia tests are well distributed in endemic countries and easy to use (Graz et al. 2011).    Certain recent developments, however, are worth considering when assessing malaria burden and control.First, the discovery of Plasmodium falciparum with deleted histidine-rich repeat region of the histidine-rich-protein 2 and the evidence that parasites not detected by HRP2 lateral flow immunoassay(LFI) cause latent infection(Koita et al. 2012), is of extreme importance in endemic countries such as Sierra Leone, where HRP2  LFIs are predominantly used. LFIs have made malaria testing ubiquitous in sub-Saharan Africa, including in very remote areas. However, false negatives resulting from deleted hrp2 in certain P.falciparum may result in lower prevalence reports. The alternative dipstick to HRP2 LFIs is the Plasmodium lactate dehydrogenase (pLDH)-based LFI. However, in Sierra Leone, the use of pLDH LFIs is less common, and a similar trend exists in the other parts of Sub-Saharan Africa. LFIs were intended to be used primarily in resource-limited locations where expert microscopists are unavailable. So the use of LFIs is not routinely duplicated with smear results in many developing countries. This could be a setback for resource-poor settings.The use of point of care, multiplex molecular detection methods have been highlighted as a means of salvaging diagnosis in resource-poor countries, but cost remains a major limitation. Notwithstanding, PCR is emerging as most sensitive malaria diagnostic apart from rapid antigen tests. Antigens and DNA may persist in blood after parasite clearance through treatment.  A plausible alternative has sought sexual stages of malaria parasites representing a small fraction of parasites during infection(Tao et al. 2014), but which can also be detected in body fluids such as saliva. Prior evidence indicates that saliva is an excellent non-invasive candidate for rapid malaria testing (Fung et al. 2012), but this aspect of malaria diagnostics is still under development including rapid tests based on nano trap technology.There has been a renewed global commitment for malaria elimination and both symptomatic and asymptomatic malaria infections are critical for the elimination of malaria. Novel diagnosis of subclinical malaria targeting sexual stages of the parasite are emerging, but the best candidate for such diagnostics are those that could be adaptable to the resource-poor settings in Africa. One such candidate is the nano trap, saliva-based, malaria rapid test that is under development by Johns Hopkins(http://www.jhsph.edu/news/news-releases/2015/johns-hopkins-bloomberg-school-of-public-health-researchers-receive-grant-to-evaluate-malaria-detection-test.html). Typhoid Fever In the case of typhoid fever, there seems to be an over-diagnosis.  The gold standard for the diagnosis of typhoid is by blood culture, which has a sensitivity of 40-60%(Parry et al. 1999), but low-cost tests, mainly the widal test, are more adaptable to resource-poverty and are commonly used in resource-poor settings such as Sierra Leone. Widal tests have been in use for over 110 years, but the results are very controversial(Olopoenia & King 2000, Nga et al. 2012),  and the test suffers from low specificity in endemic countries probably as a result of an increase in population antibody levels (Clegg et al. 1994).A positive Widal test does not always denote the presence of typhoid fever. Apart from increased population antibody levels, there exist up to 40 cross-reacting antigens between Salmonella enterica serotype Typhi and other Enterobacteriaceae(Parry et al. 1999). Cross-reacting antigens could also be from malaria, brucellosis, dengue fever, chronic liver disease or endocarditis(Colle et al. 1996).Blood culture which is the gold standard is time-consuming and may delay treatment apart from its inherently low sensitivity.  Several typhoid dipsticks have been reported, but side-by-side independent assessments in endemic countries do not always yield the expected outcome.Polymerase chain reaction is currently a better option for diagnosing typhoid fever with same day result, but cost remains a big issue in countries that could be most in need. While suitable alternatives based on economic conditions of countries are sought, the cut-off value for the widal test requires evaluation and standardization. Having a wrong diagnosis at the point of care could lead to wrong clinical outcomes.

COP27 climate change conference: urgent action needed for Africa and the world

The 2022 report of the Intergovernmental Panel on Climate Change (IPCC) paints a dark picture of the future of life on earth, characterised by ecosystem collapse, species extinction, and climate hazards such as heatwaves and floods.1 These are all linked to physical and mental health problems, with direct and indirect consequences of increased morbidity and mortality. To avoid these catastrophic health effects across all regions of the globe, there is broad agreement—as 231 health journals argued together in 2021—that the rise in global temperature must be limited to less than 1.5oC compared with pre-industrial levels

Presumptive self-diagnosis of malaria and other febrile illnesses in Sierra Leone.

INTRODUCTION The objective of this study was to evaluate the prevalence of self-diagnosis of malaria and other febrile illnesses in Bo, Sierra Leone. METHODS All households in two neighboring sections of Bo were invited to participate in a cross-sectional survey. RESULTS A total of 882 households (an 85% participation rate) that were home to 5410 individuals participated in the study. Of the 910 individuals reported to have had what the household considered to be malaria in the past month, only 41% were diagnosed by a healthcare professional or a laboratory test. Of the 1402 individuals reported to have had any type of febrile illness within the past six months, only 34% had sought a clinical or laboratory diagnosis. Self-diagnosis of influenza, yellow fever, typhoid, and pneumonia was also common. CONCLUSION Self-diagnosis and presumptive treatment with antimalarial drugs and other antibiotic medications that are readily available without a prescription may compromise health outcomes for febrile adults and children

Geographical Distribution of Intestinal Schistosomiasis and Soil-Transmitted Helminthiasis and Preventive Chemotherapy Strategies in Sierra Leone

The common intestinal roundworm, whipworm and hookworm (together known as soil-transmitted helminthes - STHs) together with schistosomes or bilharzia are responsible for extensive ill health, reduced life expectancy and death in sub-Saharan Africa. These diseases are transmitted in areas of poor water supply and sanitation. In order to implement an appropriate national control program, knowledge of the prevalence and geographical distribution of these diseases is required. A national survey was performed in Sierra Leone in 2008. Overall prevalence of intestinal schistosomiasis was 18.4% and that of STHs was 39.1%. Intestinal schistosomiasis was mainly prevalent in the northern and eastern regions while STH is widespread in the country. The results justify routine de-worming for pre-school children, school age children, women of childbearing age, and adults at high risk twice a year. The results also justify using anti-schistosomiasis drug (praziquantel) in school age children, all women of childbearing age, and adults at high risk annually or biennially depending upon the prevalence in the areas

COP27 Climate Change Conference: Urgent action needed for Africa and the world

Wealthy nations must step up support for Africa and vulnerable countries in addressing past, present and future impacts of climate change.The 2022 report of the Intergovernmental Panel on Climate Change (IPCC) paints a dark picture of the future of life on earth, characterised by ecosystem collapse, species extinction, and climate hazards such as heatwaves and floods. These are all linked to physical and mental health problems, with direct and indirect consequences of increased morbidity and mortality. To avoid these catastrophic health effects across all regions of the globe, there is broad agreement—as 231 health journals argued together in 2021—that the rise in global temperature must be limited to less than 1.5oC compared with pre-industrial levels. While the Paris Agreement of 2015 outlines a global action framework that incorporates providing climate finance to developing countries, this support has yet to materialise. COP27 is the fifth Conference of the Parties (COP) to be organised in Africa since its inception in 1995. Ahead of this meeting, we—as health journal editors from across the continent—call for urgent action to ensure it is the COP that finally delivers climate justice for Africa and vulnerable countries. This is essential not just for the health of those countries, but for the health of the whole world

COP27 Climate Change Conference: urgent action needed for Africa and the world

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COP27 climate change conference: Urgent action needed for Africa and the world

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Isolation of Angola-like Marburg virus from Egyptian rousette bats from West Africa.

Marburg virus (MARV) causes sporadic outbreaks of severe Marburg virus disease (MVD). Most MVD outbreaks originated in East Africa and field studies in East Africa, South Africa, Zambia, and Gabon identified the Egyptian rousette bat (ERB; Rousettus aegyptiacus) as a natural reservoir. However, the largest recorded MVD outbreak with the highest case-fatality ratio happened in 2005 in Angola, where direct spillover from bats was not  shown. Here, collaborative studies by the Centers for Disease Control and Prevention, Njala University, University of California, Davis USAID-PREDICT, and the University of Makeni identify MARV circulating in ERBs in Sierra Leone. PCR, antibody and virus isolation data from 1755 bats of 42 species shows active MARV infection in approximately 2.5% of ERBs. Phylogenetic analysis identifies MARVs that are similar to the Angola strain. These results provide evidence of MARV circulation in West Africa and demonstrate the value of pathogen surveillance to identify previously undetected threats