Review of Lassa fever, an emerging old world haemorrhagic viral disease in sub-Saharan Africa

Bluetongue (BT) is an arthropod-borne viral disease of ruminants with serious trade and socio-economic implications. Although the disease has been reported in a number of countries in sub-Saharan Africa, there is currently no information on circulating serotypes and disease distribution in Zambia. Following surveillance for BT in domestic and wild ruminants in Zambia, BT virus (BTV) nucleic acid and antibodies were detected in eight of the 10 provinces of the country. About 40% (87/215) of pooled blood samples from cattle and goats were positive for BTV nucleic acid, while one hartebeest pool (1/43) was positive among wildlife samples. Sequence analysis of segment 2 revealed presence of serotypes 3, 5, 7, 12 and 15, with five nucleotypes (B, E, F, G and J) being identified. Segment 10 phylogeny showed Zambian BTV sequences clustering with Western topotype strains from South Africa, intimating likely transboundary spread of BTV in Southern Africa. Interestingly, two Zambian viruses and one isolate from Israel formed a novel clade, which we designated as Western topotype 4. The high seroprevalence (96.2%) in cattle from Lusaka and Central provinces and co-circulation of multiple serotypes showed that BT is widespread, underscoring the need for prevention and control strategies.

Download Full-text

Cross-Reactive Antibodies to SARS-CoV-2 and MERS-CoV in Pre-COVID-19 Blood Samples from Sierra Leonians

Viruses ◽

10.3390/v13112325 ◽

2021 ◽

Vol 13 (11) ◽

pp. 2325

Author(s):

Rodrigo Borrega ◽

Diana K. S. Nelson ◽

Anatoliy P. Koval ◽

Nell G. Bond ◽

Megan L. Heinrich ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Blood Donors ◽

Middle Eastern ◽

The United States ◽

Lassa Fever ◽

Sub Saharan Africa ◽

Blood Samples ◽

Sierra Leonean ◽

Potential Factor ◽

Sub Saharan

Many countries in sub-Saharan Africa have experienced lower COVID-19 caseloads and fewer deaths than countries in other regions worldwide. Under-reporting of cases and a younger population could partly account for these differences, but pre-existing immunity to coronaviruses is another potential factor. Blood samples from Sierra Leonean Lassa fever and Ebola survivors and their contacts collected before the first reported COVID-19 cases were assessed using enzyme-linked immunosorbent assays for the presence of antibodies binding to proteins of coronaviruses that infect humans. Results were compared to COVID-19 subjects and healthy blood donors from the United States. Prior to the pandemic, Sierra Leoneans had more frequent exposures than Americans to coronaviruses with epitopes that cross-react with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), SARS-CoV, and Middle Eastern respiratory syndrome coronavirus (MERS-CoV). The percentage of Sierra Leoneans with antibodies reacting to seasonal coronaviruses was also higher than for American blood donors. Serological responses to coronaviruses by Sierra Leoneans did not differ by age or sex. Approximately a quarter of Sierra Leonian pre-pandemic blood samples had neutralizing antibodies against SARS-CoV-2 pseudovirus, while about a third neutralized MERS-CoV pseudovirus. Prior exposures to coronaviruses that induce cross-protective immunity may contribute to reduced COVID-19 cases and deaths in Sierra Leone.

Download Full-text

Genomic balancing selection is key to the invasive success of the fall armyworm

10.1101/2020.06.17.154880 ◽

2020 ◽

Author(s):

Sudeeptha Yainna ◽

Wee Tek Tay ◽

Estelle Fiteni ◽

Fabrice Legeai ◽

Anne-Laure Clamens ◽

...

Keyword(s):

West Africa ◽

Population Genomics ◽

Balancing Selection ◽

Fall Armyworm ◽

Western Hemisphere ◽

Sub Saharan Africa ◽

Old World ◽

Native Populations ◽

Mild Reduction ◽

Sub Saharan

AbstractA successful biological invasion involves survival in a newly occupied environment. If a population bottleneck occurs during an invasion, the resulting depletion of genetic variants could cause increased inbreeding depression and decreased adaptive potential, which may result in a fitness reduction. How invasive populations survive in the newly occupied environment despite reduced heterozygosity and how, in many cases, they maintain moderate levels of heterozygosity are still contentious issues1. The Fall armyworm (FAW; Lepidoptera: Spodoptera frugiperda), a polyphagous pest, is native to the Western hemisphere. Its invasion in the Old World was first reported from West Africa in early 2016, and in less than four years, it swept sub-Saharan Africa and Asia, finally reaching Australia. We used population genomics approaches to investigate the factors that may explain the invasive success of the FAW. Here we show that genomic balancing selection played a key role in invasive success by restoring heterozygosity before the global invasion. We observe a drastic loss of mitochondrial polymorphism in invasive populations, whereas nuclear heterozygosity exhibits a mild reduction. The population from Benin in West Africa has the lowest length of linkage disequilibrium amongst all invasive and native populations despite its reduced population size. This result indicates that balancing selection increased heterozygosity by facilitating the admixture of invasive populations from distinct origins and that, once heterozygosity was sufficiently high, FAW started spreading globally in the Old World. As comparable heterozygosity levels between invasive and native populations are commonly observed1, we postulate that the restoration of heterozygosity through balancing selection could be widespread among successful cases of biological invasions.

Download Full-text

Global Patterns of Ruler Conversion to Islam and the Logic of Empirical Religiosity

Islamisation ◽

10.3366/edinburgh/9781474417129.003.0002 ◽

2017 ◽

pp. 21-55

Author(s):

Alan Strathern

Keyword(s):

Southeast Asia ◽

Central Asia ◽

Far East ◽

Sub Saharan Africa ◽

The South ◽

Old World ◽

The Far East ◽

Conversion To Islam ◽

Global Patterns ◽

Sub Saharan

The first great expansion of Islam owed little to the conversion of rulers but instead followed, albeit slowly, in the footsteps of strikingly rapid military conquest. Yet, in the second millennium, Islam expanded further and faster by means of ruler conversions than its proselytising rivals, Christianity and Buddhism. The principal regions where this held true were Sub-Saharan Africa and maritime Southeast Asia, though Central Asia also saw numerous conversions of the Mongol and Turkic elites that poured into the region.1 This was the period, then, in which Islam broke out of its Mediterranean and West Asian base to penetrate new territories to the south and the far east of the old world.

Download Full-text

EPIZOOTIOLOGICAL SITUATION OF АFRICAN SWINE FEVER IN EUROPE

Archives of Veterinary Medicine ◽

10.46784/e-avm.v10i2.67 ◽

2017 ◽

Vol 10 (2) ◽

pp. 13-22

Author(s):

Vesna Milićević ◽

Vladimir Radosavljević ◽

Ljubiša Veljović ◽

Jelena Maksimović-Zorić ◽

Sonja Radojičić

Keyword(s):

Wild Boar ◽

Viral Entry ◽

African Swine Fever ◽

Viral Disease ◽

Control Measures ◽

Sub Saharan Africa ◽

Domestic Pigs ◽

Source Of Infection ◽

Sub Saharan ◽

And Control

African swine fever (ASF) is a viral disease of domestic pigs and wild boar. Due to the very serious socioeconomic consequences, the disease isone of the most important ones nowadays. African swine fever is an enzootic disease in many countries in Sub-Saharan Africa, in Sardinia, and TransCaucasus countries. Aft er its occurrence in Georgia in 2007, ASF spread to Armenia and Russian Federation, and in 2008. to Azerbaijan. Since then,its progressive moving toward the west has been recorded. Despite the number of undertaken preventive and control measures in the EuropeanUnion (EU), ASF has been still spreading. During 2017, the disease has been reported in domestic pigs in Estonia, Italy-Sardinia, Latvia, Lithuania,Poland, Romania, and Ukraine. ASF cases in domestic pigs have also been reported in Moldova in 2017. Th e number of diagnosed cases in wild boarin 2017 is much higher than in domestic pigs. ASF outbreak in wild boar in the Czech Republic well describes the possible viral „jump“ into a newregion. Th e source of infection hasn’t been confi rmed yet, but it is common that such leaps are due to either swill feeding or improperly disposal of food rather than to the animal movements. Since the lack of eff ective vaccine makes eradication even more diffi cult, the prevention of viral entry into the new areas is of the most importance. With the same aim, since 2011. the surveillance of ASF has been implemented in Serbia.

Download Full-text

Insights into the Evolutionary Origin of Mediterranean Sandfly Fever Viruses

mSphere ◽

10.1128/msphere.00598-20 ◽

2020 ◽

Vol 5 (5) ◽

Author(s):

Marco Marklewitz ◽

David P. Tchouassi ◽

Christian Hieke ◽

Verena Heyde ◽

Baldwyn Torto ◽

...

Keyword(s):

Genetic Diversity ◽

Rift Valley ◽

Common Ancestor ◽

Febrile Illness ◽

Sub Saharan Africa ◽

Recent Common Ancestor ◽

Toscana Virus ◽

Sister Relationship ◽

Old World ◽

Sub Saharan

ABSTRACT Sandfly-transmitted phleboviruses (family Phenuiviridae, order Bunyavirales) are associated with febrile illness and infections of the nervous system in humans. These viruses are almost exclusively found in tropical areas of the New World and restricted to semiarid and temperate zones in the Old World. Here, we discovered seven strains of four previously unknown phleboviruses, named Bogoria virus (BOGV), Embossos virus (EMRV), Kiborgoch virus (KBGV), and Perkerra virus (PERV), as well as the recently discovered Ntepes virus, in sandflies collected in the Kenyan Rift Valley. The genomes have a tripartite organization with conserved termini typical of phleboviruses. LOBV, PERV, and EMBV showed low similarity to known phleboviruses, with less than 55% pairwise amino acid identities in the RNA-directed RNA polymerase (RdRp) proteins, and defined a highly diversified monophyletic clade in sister relationship to the sandfly fever Sicilian serocomplex. All three viruses failed to react with sandfly fever Sicilian virus antisera in recombinant immunofluorescence assays (rIFA), suggesting that the viruses belong to a yet-unknown serogroup. In contrast, KBGV was closely related to Toscana virus (84% identity of RdRp proteins) and shared a most recent common ancestor with the clade comprising sandfly fever Naples and Toscana viruses. KBGV reacted with sandfly fever Naples and Toscana virus antisera in rIFA. The genetic diversity of the detected viruses and their phylogenetic positions implies that the Old World sandfly-borne phleboviruses originated from sub-Saharan Africa. Importantly, our findings suggest that diseases associated with sandfly-borne phlebovirus infections may also affect the Kenyan population. IMPORTANCE Studies on the genetic diversity of arthropod-borne viruses circulating in rural regions can provide critical early indications on new emerging viruses essential for global epidemic preparedness. In this study, we describe the discovery of four phleboviruses in sandflies from the Kenyan Rift Valley. The novel viruses are related to the two medically important serocomplexes, sandfly fever Naples and sandfly fever Sicilian, that are associated with febrile illness and neuroinvasive infections and which were previously not known to occur in sub-Saharan Africa. Knowledge on the occurrence of sandfly-borne phleboviruses in Kenya and elsewhere in Africa can help to decipher their contributions in the etiologies of fevers of unknown origin in patients. Our findings on five genetically diverse phleboviruses detected in Kenya suggest that the common ancestor of Old World phleboviruses existed in sub-Saharan Africa, a hot spot for emerging arboviruses.

Download Full-text

Establishment of a Genetically Confirmed Breeding Colony of Mastomys natalensis from Wild-Caught Founders from West Africa

Viruses ◽

10.3390/v13040590 ◽

2021 ◽

Vol 13 (4) ◽

pp. 590

Author(s):

David Safronetz ◽

Kyle Rosenke ◽

Robert J. Fischer ◽

Rachel A. LaCasse ◽

Dana P. Scott ◽

...

Keyword(s):

West Africa ◽

Lassa Fever ◽

Sub Saharan Africa ◽

Microbial Pathogens ◽

Lassa Virus ◽

Mastomys Natalensis ◽

Emerging Pathogens ◽

Breeding Colony ◽

Sub Saharan ◽

Laboratory Breeding

Mastomys natalensis are a ubiquitous and often dominant rodent across sub-Saharan Africa. Importantly, they are a natural reservoir for microbial pathogens including Lassa virus (LASV), the etiological agent of Lassa fever in humans. Lassa-infected rodents have been documented across West Africa and coincide with regions where annual outbreaks occur. Zoonotic transmission to humans most often occurs directly from infected rodents. Little is known about LASV infection kinetics and transmissibility in M.natalensis, primarily due to available animals. Here, we describe the establishment of a laboratory breeding colony of genetically confirmed M.natalensis from wild-captured rodents. This colony will provide a convenient source of animals to study LASV and other emerging pathogens that utilize M. natalensis in their enzootic lifecycles.

Download Full-text

The Promise, Problems, and Pitfalls of Including Pregnant Women in Lassa Fever Vaccine Clinical Trials: A Qualitative Analysis of Sub-Sahara Africa Investigators' Perception

10.21203/rs.3.rs-712696/v1 ◽

2021 ◽

Author(s):

Kolawole A Salami ◽

Henshaw E Mandi ◽

Nathalie Imbault ◽

Nadia G Tornieporth

Keyword(s):

Clinical Trials ◽

Pregnant Women ◽

Community Engagement ◽

Safety Data ◽

Lassa Fever ◽

West African ◽

Sub Saharan Africa ◽

African Countries ◽

Sub Saharan ◽

Promise Problems

Abstract Background Lassa fever run a uniquely severe course in pregnancy. There are plans for Lassa fever vaccine clinical trials in endemic West African countries. We tried to assess the perception of West African investigators to including pregnant women in these studies. Methods Interviews were conducted with eight investigators from sub-Saharan Africa. Six of them from West Africa. Data were analyzed thematically. Results Respondents had limited experience with pregnant women in clinical trials but desired a paradigm shift. They identified pregnant women's willingness, a robust community engagement strategy, and adequate safety data as enablers, while lack of safety data, persistent fears about potential harm to pregnant women and offspring, and inappropriate community engagement activities as potential barriers. Conclusion The inclusion of pregnant women in Lassa fever vaccine clinical trials should be a priority of vaccine developers. Investigators are willing to conduct these studies provided adequate measures to ensure safety is in place.

Download Full-text

RTS,S/AS01, a vaccine targeting pre-erythrocytic stages of Plasmodium falciparum

Emerging Topics in Life Sciences ◽

10.1042/etls20170101 ◽

2017 ◽

Vol 1 (6) ◽

pp. 533-537

Author(s):

Lorenz von Seidlein ◽

Borimas Hanboonkunupakarn ◽

Podjanee Jittmala ◽

Sasithon Pukrittayakamee

Keyword(s):

Protective Efficacy ◽

Age Groups ◽

Sub Saharan Africa ◽

Phase Iii ◽

European Medicines Agency ◽

Older Children ◽

Pivotal Phase ◽

Malaria Epidemiology ◽

Maximum Benefit ◽

Sub Saharan

RTS,S/AS01 is the most advanced vaccine to prevent malaria. It is safe and moderately effective. A large pivotal phase III trial in over 15 000 young children in sub-Saharan Africa completed in 2014 showed that the vaccine could protect around one-third of children (aged 5–17 months) and one-fourth of infants (aged 6–12 weeks) from uncomplicated falciparum malaria. The European Medicines Agency approved licensing and programmatic roll-out of the RTSS vaccine in malaria endemic countries in sub-Saharan Africa. WHO is planning further studies in a large Malaria Vaccine Implementation Programme, in more than 400 000 young African children. With the changing malaria epidemiology in Africa resulting in older children at risk, alternative modes of employment are under evaluation, for example the use of RTS,S/AS01 in older children as part of seasonal malaria prophylaxis. Another strategy is combining mass drug administrations with mass vaccine campaigns for all age groups in regional malaria elimination campaigns. A phase II trial is ongoing to evaluate the safety and immunogenicity of the RTSS in combination with antimalarial drugs in Thailand. Such novel approaches aim to extract the maximum benefit from the well-documented, short-lasting protective efficacy of RTS,S/AS01.

Download Full-text

Mortality and Society in Sub-Saharan Africa

Population Studies ◽

10.1080/0032472031000147416 ◽

1993 ◽

Vol 47 (3) ◽

pp. 555-556

Author(s):

Lado Ruzicka

Keyword(s):

Sub Saharan Africa ◽

Sub Saharan

Download Full-text