Banana Die-Back Virus - a New Virus Infecting Banana in Nigeria

Two viruses naturally infect Musa in Nigeria: banana streak badnavirus (BSV) and cucumber mosaic cucumovirus (CMV). During a recent field survey at Ibadan (Nigeria), some severely stunted banana plants (cv. Valery) were found that tested negative for CMV, banana bunchy-top virus, and BSV. The plants had symptoms of leaf crinkling, leaf necrosis, and cigar-leaf die-back. Subsequent suckers from the same mats were progressively more stunted. A 28- to 30-nm isometric virus was purified, and used for the production of antibodies, from the affected plants with (NH4)2SO4 to precipitate the virus. The antiserum (titer of 1:10,000) was used in enzyme-linked immunosorbent assay and immunosorbent electron microscopy to detect the virus. Mechanical inoculation with partially purified virus preparations resulted in stunting and development of pinpoint chlorotic lesions on Vigna unguiculata TVu-76 and symptomless systemic infection of Nicotiana occidentalis. The virus was not mechanically transmissible from N. occidentalis to banana. A serological relationship between this virus, banana die-back virus (BDBV), and tobacco ringspot, tomato ringspot, and cacao necrosis nepoviruses was found. The nematode species around the affected banana plants were isolated: Helicotylenchus multicinctus (Cobb) Golden was the dominant species, low numbers of H. dihystera (Cobb) Sher were present, but no virustransmitting nematodes were found in soil or banana roots. Further studies are needed to determine the mode of spread of BDBV, the implications for banana/plantain production in sub-Saharan Africa, and the safe international movement of germplasm.

Download Full-text

A Case for Regular Aflatoxin Monitoring in Peanut Butter in Sub-Saharan Africa: Lessons from a 3-Year Survey in Zambia

Journal of Food Protection ◽

10.4315/0362-028x.jfp-15-542 ◽

2016 ◽

Vol 79 (5) ◽

pp. 795-800 ◽

Cited By ~ 17

Author(s):

SAMUEL M. C. NJOROGE ◽

LIMBIKANI MATUMBA ◽

KENNEDY KANENGA ◽

MOSES SIAMBI ◽

FARID WALIYAR ◽

...

Keyword(s):

South Africa ◽

Aflatoxin B1 ◽

Peanut Butter ◽

Aflatoxin Contamination ◽

Comprehensive Analysis ◽

Sub Saharan Africa ◽

Enzyme Linked Immunosorbent Assay ◽

Contamination Level ◽

Batch Number ◽

Sub Saharan

ABSTRACT A 3-year comprehensive analysis of aflatoxin contamination in peanut butter was conducted in Zambia, sub-Saharan Africa. The study analyzed 954 containers of 24 local and imported peanut butter brands collected from shops in Chipata, Mambwe, Petauke, Katete, and Nyimba districts and also in Lusaka from 2012 to 2014. For analysis, a sample included six containers of a single brand, from the same processing batch number and the same shop. Each container was quantitatively analyzed for aflatoxin B1 (AFB1) in six replicates by using competitive enzyme-linked immunosorbent assay; thus, aflatoxin contamination level of a given sample was derived from an average of 36 test values. Results showed that 73% of the brands tested in 2012 were contaminated with AFB1 levels >20 μg/kg and ranged up to 130 μg/kg. In 2013, 80% of the brands were contaminated with AFB1 levels >20 μg/kg and ranged up to 10,740 μg/kg. Compared with brand data from 2012 and 2013, fewer brands in 2014, i.e., 53%, had aflatoxin B1 levels >20 μg/kg and ranged up to 1,000 μg/kg. Of the eight brands tested repeatedly across the 3-year period, none consistently averaged ≤20 μg/kg. Our survey clearly demonstrates the regular occurrence of high levels of AF B1 in peanut butter in Zambia. Considering that some of the brands tested originated from neighboring countries such as Malawi, Zimbabwe, and South Africa, the current findings provide a sub-Saharan regional perspective regarding the safety of peanut butter.

Download Full-text

First Report of East African Cassava Mosaic Begomovirus in Nigeria

Plant Disease ◽

10.1094/pdis.1999.83.4.398a ◽

1999 ◽

Vol 83 (4) ◽

pp. 398-398 ◽

Cited By ~ 14

Author(s):

F. O. Ogbe ◽

G. I. Atiri ◽

D. Robinson ◽

S. Winter ◽

A. G. O. Dixon ◽

...

Keyword(s):

Central Africa ◽

Mosaic Disease ◽

Sub Saharan Africa ◽

Cassava Mosaic Disease ◽

Enzyme Linked Immunosorbent Assay ◽

East African ◽

African Countries ◽

Manihot Esculenta Crantz ◽

Cross River State ◽

Sub Saharan

Cassava (Manihot esculenta Crantz) is an important food crop in sub-Saharan Africa. One of the major production constraints is cassava mosaic disease caused by African cassava mosaic (ACMV) and East African cassava mosaic (EACMV) begomoviruses. ACMV is widespread in its distribution, occurring throughout West and Central Africa and in some eastern and southern African countries. In contrast, EACMV has been reported to occur mainly in more easterly areas, particularly in coastal Kenya and Tanzania, Malawi, and Madagascar. In 1997, a survey was conducted in Nigeria to determine the distribution of ACMV and its strains. Samples from 225 cassava plants showing mosaic symptoms were tested with ACMV monoclonal antibodies (MAbs) in triple antibody sandwich enzyme-linked immunosorbent assay (1). Three samples reacted strongly with MAbs that could detect both ACMV and EACMV. One of them did not react with ACMV-specific MAbs while the other two reacted weakly with such MAbs. With polymerase chain reaction (2), the presence of EACMV and a mixture of EACMV and ACMV in the respective samples was confirmed. These samples were collected from two villages: Ogbena in Kwara State and Akamkpa in Cross River State. Co-infection of some cassava varieties with ACMV and EACMV leads to severe symptoms. More importantly, a strain of mosaic geminivirus known as Uganda variant arose from recombination between the two viruses (2). This report provides evidence for the presence of EACMV in West Africa. References: (1) J. E. Thomas et al. J. Gen. Virol. 67:2739, 1986. (2) X. Zhou et al. J. Gen. Virol. 78:2101, 1997.

Download Full-text

Molecular Diversity of Nematode Parasites in Afrotropical Reed Frogs (Hyperolius spp.)

Diversity ◽

10.3390/d12070265 ◽

2020 ◽

Vol 12 (7) ◽

pp. 265

Author(s):

Ulrich Sinsch ◽

J. Maximilian Dehling ◽

Patrick Scheid ◽

Carsten Balczun

Keyword(s):

Dna Sequences ◽

Nematode Species ◽

Sub Saharan Africa ◽

Parasitic Nematodes ◽

Marker Genes ◽

Nematode Parasites ◽

Diversity Assessment ◽

Wide Range ◽

Nematode Diversity ◽

Sub Saharan

The diversity of nematodes infecting amphibians is understudied in tropical Africa and unknown in Rwanda. Diversity assessment is hampered by the fact that species descriptions refer mostly to morphological features that are unlinked to DNA sequences of marker genes available in public databases. In this paper, we explore the abundance and diversity of parasitic nematodes in reed frogs Hyperolius kivuensis (n = 115), H. parallelus (n = 45) and H. viridiflavus (n = 100) collected in Rwanda. Five nematode species were identified morphologically as Orneoascaris chrysanthemoides, O. schoutedeni, Gendria leberrei, Aplectana chamaeleonis and Rhabdias collaris. Corresponding DNA sequences of 18S and COI genes were determined and subsequently deposited in GenBank. Aplectana chamaeleonis showed the highest prevalence (8.7%), but O. chrysanthemoides the highest mean intensity of infection (6.0) and largest number (24) of individuals in H. kivuensis. To the best of our knowledge, all amphibian hosts are new records for these nematode species, which are known to infect a wide range of amphibian and reptile species. Our findings suggest that nematode diversity is probably lower than previously assumed due to low host specificity. As morphological species identification is often challenging, our data facilitate molecular identification of adult and specifically larval nematodes found in amphibians of Sub-Saharan Africa.

Download Full-text

No Confirmed Cases of Taenia solium Taeniasis in a Group of Recently Arrived Sub-Saharan Migrants to Italy

Pathogens ◽

10.3390/pathogens8040296 ◽

2019 ◽

Vol 8 (4) ◽

pp. 296 ◽

Cited By ~ 1

Author(s):

Lorenzo Zammarchi ◽

Marta Tilli ◽

Antonia Mantella ◽

Annarita Botta ◽

Alessandra Nicoletti ◽

...

Keyword(s):

Positive Result ◽

Taenia Solium ◽

Sub Saharan Africa ◽

Enzyme Linked Immunosorbent Assay ◽

False Positive Result ◽

Specific Enzyme ◽

Density Values ◽

Sub Saharan ◽

Autochthonous Transmission

One-hundred and sixty-four migrants from Sub-Saharan Africa to Italy were screened with the Taenia solium specific enzyme-linked immunosorbent assay coproantigen (ELISA CoAg) and four (2.4%) were recorded as positive, but with optical density values near to the cut-off. No ELISA CoAg positive samples were confirmed by parasitological methods. Low positivity could be attributed to false positive result or cross-reaction with other Taenia species. Further studies are needed to assess the role of migration on sporadic autochthonous transmission of T. solium taeniasis/cysticercosis in Europe.

Download Full-text

Development of a Novel Cocktail Enzyme-Linked Immunosorbent Assay and a Field-Applicable Lateral-Flow Rapid Test for Diagnosis of Contagious Bovine Pleuropneumonia

Journal of Clinical Microbiology ◽

10.1128/jcm.03259-15 ◽

2016 ◽

Vol 54 (6) ◽

pp. 1557-1565 ◽

Cited By ~ 1

Author(s):

Martin Heller ◽

Nimmo Gicheru ◽

Georgina Tjipura-Zaire ◽

Cecilia Muriuki ◽

Mingyan Yu ◽

...

Keyword(s):

Immunosorbent Assay ◽

Rapid Test ◽

Lateral Flow ◽

Sub Saharan Africa ◽

Enzyme Linked Immunosorbent Assay ◽

Contagious Bovine Pleuropneumonia ◽

Serum Samples ◽

Content Type ◽

Mycoplasma Mycoides ◽

Sub Saharan

Contagious bovine pleuropneumonia (CBPP) is a severe respiratory disease that is widespread in sub-Saharan Africa. It is caused byMycoplasma mycoidessubsp.mycoides, a bacterium belonging to theMycoplasma mycoidescluster. In the absence of an efficient CBPP vaccine, improved and easy-to-use diagnostic assays for recurrent testing combined with isolation and treatment of positive animals represent an option for CBPP control in Africa. Here we describe the comprehensive screening of 17 immunogenicMycoplasma mycoidessubsp.mycoidesproteins using well-characterized bovine sera for the development of a novel cocktail enzyme-linked immunosorbent assay (ELISA) for laboratory use. Two recombinantMycoplasmaimmunogens, MSC_0136 and MSC_0636, were used to set up a standardized cocktail ELISA protocol. According to the results from more than 100 serum samples tested, the sensitivity and specificity of the novel cocktail ELISA were 85.6% and 96.4%, respectively, with an overall diagnostic accuracy comparable to that of the Office International des Epizooties (OIE)-prescribed serological assays. In addition, we provide a proof of principle for a field-applicable, easy-to-use commercially produced prototype lateral-flow test for rapid (<30-min) diagnosis of CBPP.

Download Full-text

Human Immunodeficiency Virus (HIV) and Treponema pallidum (Syphilis) Co-infection in Uyo, Nigeria

International STD Research & Reviews ◽

10.9734/isrr/2020/v9i230112 ◽

2020 ◽

pp. 33-42

Author(s):

Iheanyi O. Okonko ◽

Hope C. Innocent- Adiele ◽

Amaka M. Awanye ◽

Tochi I. Cookey ◽

Charles C. Onoh

Keyword(s):

Reproductive Health ◽

Hiv Transmission ◽

Human Subjects ◽

Treponema Pallidum ◽

Educational Background ◽

Sub Saharan Africa ◽

Enzyme Linked Immunosorbent Assay ◽

Early Screening ◽

Medical Male Circumcision ◽

Sub Saharan

Aim: HIV/AIDS remains a leading cause of death and disability in Sub Saharan Africa and this accounts for almost half of the world’s HIV related deaths. On the other hand, bacterial sexually transmitted diseases (STDs) such as syphilis contributes to the morbidity and mortality obtained in developing countries. Co-infection of syphilis and HIV may increase the risk of HIV transmission and adversely affect reproductive health. Prompt diagnosis and treatment of STDs in HIV positive individuals can help prevent spread to their partners. There is also very little information about incidence and prevalence of HIV/Syphilis co-infection and their determinants. The aim of this study is to evaluate the HIV/Syphilis co-infection among HIV-infected individuals in Uyo, Nigeria. Methods: A total of 176 individuals living with HIV participated in this study. The average age of the study participants was 39.1 years from a range of 6-67 years. Plasma samples obtained from the human subjects were analysed for presence of HIV and Syphilis antibodies using enzyme-Linked immunosorbent Assay. Results: Our findings showed that the overall prevalence of HIV/Syphilis co-infection in Uyo was 1.7%. Analysis of the results revealed that the variables—sex and educational background—significantly influenced the rate of syphilis sero-positivity among the population under study. While variables- age, marital status and occupational skills non-significantly influenced the rate of syphilis sero-positivity among the population under study. Conclusion: This study confirmed the co-infection of HIV and Syphilis in Uyo, Nigeria. Early screening of Syphilis and other STDs contributes to the control of infection and reduces the spread of HIV to partners. A number of primary preventive interventions for HIV and syphilis need to be adopted including use of condoms and medical male circumcision in order to improve sexual and reproductive health amongst individuals.

Download Full-text

Plasmodium ovale: Parasite and Disease

Clinical Microbiology Reviews ◽

10.1128/cmr.18.3.570-581.2005 ◽

2005 ◽

Vol 18 (3) ◽

pp. 570-581 ◽

Cited By ~ 125

Author(s):

William E. Collins ◽

Geoffrey M. Jeffery

Keyword(s):

Public Health Problem ◽

Molecular Techniques ◽

Sub Saharan Africa ◽

Enzyme Linked Immunosorbent Assay ◽

Developmental Cycle ◽

Major Public Health Problem ◽

Plasmodium Ovale ◽

Malaria Parasites ◽

Sub Saharan

SUMMARY Humans are infected by four recognized species of malaria parasites. The last of these to be recognized and described is Plasmodium ovale. Like the other malaria parasites of primates, this parasite is only transmitted via the bites of infected Anopheles mosquitoes. The prepatent period in the human ranges from 12 to 20 days. Some forms in the liver have delayed development, and relapse may occur after periods of up to 4 years after infection. The developmental cycle in the blood lasts approximately 49 h. An examination of records from induced infections indicated that there were an average of 10.3 fever episodes of ≥101°F and 4.5 fever episodes of ≥104°F. Mean maximum parasite levels were 6,944/μl for sporozoite-induced infections and 7,310/μl for trophozoite-induced infections. Exoerythrocytic stages have been demonstrated in the liver of humans, chimpanzees, and Saimiri monkeys following injection of sporozoites. Many different Anopheles species have been shown to be susceptible to infection with P. ovale, including A. gambiae, A. atroparvus, A. dirus, A. freeborni, A. albimanus, A. quadrimaculatus, A. stephensi, A. maculatus, A. subpictus, and A. farauti. An enzyme-linked immunosorbent assay has been developed to detect mosquitoes infected with P. ovale using a monoclonal antibody directed against the circumsporozoite protein. Plasmodium ovale is primarily distributed throughout sub-Saharan Africa. It has also been reported from numerous islands in the western Pacific. In more recent years, there have been reports of its distribution on the Asian mainland. Whether or not it will become a major public health problem there remains to be seen. The diagnosis of P. ovale is based primarily on the characteristics of the blood stages and its differentiation from P. vivax. The sometimes elliptical shape of the infected erythrocyte is often diagnostic when combined with other, subtler differences in morphology. The advent of molecular techniques, primarily PCR, has made diagnostic confirmation possible. The development of techniques for the long-term frozen preservation of malaria parasites has allowed the development diagnostic reference standards for P. ovale. Infections in chimpanzees are used to provide reference and diagnostic material for serologic and molecular studies because this parasite has not been shown to develop in other nonhuman primates, nor has it adapted to in vitro culture. There is no evidence to suggest that P. ovale is closely related phylogenetically to any other of the primate malaria parasites that have been examined.

Download Full-text

Antigen-based diagnosis of Schistosoma infection in travellers: a prospective study

Journal of Travel Medicine ◽

10.1093/jtm/taaa055 ◽

2020 ◽

Vol 27 (4) ◽

Author(s):

Miriam Casacuberta-Partal ◽

Jacqueline J Janse ◽

Roos van Schuijlenburg ◽

Jutte J C de Vries ◽

Marianne A A Erkens ◽

...

Keyword(s):

Prospective Study ◽

Adult Worm ◽

Signs And Symptoms ◽

Diagnostic Value ◽

Sub Saharan Africa ◽

Enzyme Linked Immunosorbent Assay ◽

Water Contact ◽

Praziquantel Treatment ◽

Sub Saharan ◽

A Prospective Study

Abstract Background Travellers infected with Schistosoma spp. might be pauci- or even asymptomatic on first presentation. Therefore, schistosomiasis may remain undiagnosed in this population. Active infection, as evidenced by the presence of the tissue-dwelling worm, can be demonstrated via the detection of adult worm-derived circulating anodic antigen (CAA) utilising a robust well-described lateral flow-(LF) based test applying background-free up-converting reporter particles (UCP). In this prospective study, we assessed the diagnostic value of serum and urine UCP-LF CAA test in comparison with two Schistosoma-specific serological assays detecting antibodies against adult worm antigen-immuno fluorescence assay (AWA-IFA) and against soluble egg antigen–enzyme-linked immunosorbent assay (SEA-ELISA) antigens in travellers. Methods Samples were collected from 106 Dutch travellers who reported freshwater contact in sub-Saharan Africa and who were recruited up to 2 years after return. Subjects were asked to complete a detailed questionnaire on travel history, water contact, signs and symptoms compatible with schistosomiasis. Results Two travellers were positive by serum CAA and an additional one by urine CAA. A total of 22/106 (21%) samples were antibody positive by AWA-IFA and 9/106 (9%) by SEA-ELISA. At follow-up 6 weeks and 6 months after praziquantel treatment, all seropositives remained antibody positive whereas CAA was cleared. Seropositivity could not be predicted by the type of fresh water-related activity, country visited or symptoms reported. Conclusion The low number of UCP-LF CAA positives suggests that in travellers, active infections often do not establish or have very low worm burden. Based on our high seroconversion rates, we conclude that the AWA-IFA assay is the most sensitive test to detect schistosome exposure. Given the lack of predictive symptoms or risk factors, we recommend schistosomiasis screening at least by serology in all travellers with reported freshwater contact in high-endemic areas.

Download Full-text

Cultural and socio-economic conditions as factors contributing to chronic stress in sub-Saharan African communities

Canadian Journal of Physiology and Pharmacology ◽

10.1139/cjpp-2014-0035 ◽

2014 ◽

Vol 92 (9) ◽

pp. 725-732 ◽

Cited By ~ 16

Author(s):

Phaedra Henley ◽

Megan Lowthers ◽

Gideon Koren ◽

Pamela Tsimbiri Fedha ◽

Evan Russell ◽

...

Keyword(s):

Chronic Stress ◽

Reference Group ◽

Sub Saharan Africa ◽

Economic Conditions ◽

Enzyme Linked Immunosorbent Assay ◽

Hair Cortisol ◽

Hair Samples ◽

The Mean ◽

Sub Saharan ◽

Slum Settlements

Stress is known to contribute to overall health status. Many individuals in sub-Saharan Africa are believed to be stressed about their employment, income, and health. This study aimed to investigate hair cortisol as a biomarker of chronic stress in settlement communities in Kenya. Hair samples were collected from 108 volunteers from settlement communities in Kenya. An enzyme-linked immunosorbent assay technique was used to measure hair cortisol concentrations. In parallel, a health survey was completed. The mean ± SD for the cortisol concentration in the hair of volunteers from the settlement communities in Naivasha was 639 ± 300 ng/g, which was higher than found for a Caucasian reference group (299 ± 110 ng/g; one-way ANOVA, P = 0.0003). There were no differences in hair cortisol concentrations between members of slum settlements adjacent to large floriculture farms in Naivasha (Karagita, Kamere/Kwa Muhia/DCK, and Kasarani) compared with those well-removed from all floriculture in Mogotio (Mogotio and Westlands/Katorongot). However, hair cortisol concentrations were significantly higher in females, divorced volunteers, those who made below minimum wage, and those who reported feeling unsafe collecting water or using sanitation facilities within these 2 settlement groups. We found no evidence for increased chronic stress (measured by hair cortisol content) between members of slum settlements adjacent to versus distant to large floriculture farms. Cultural and socio-economic conditions that prevail in much of sub-Saharan Africa were found to be factors contributing to chronic stress.

Download Full-text

The role of a single non-coding nucleotide in the evolution of an epidemic African clade of Salmonella

10.1101/175265 ◽

2017 ◽

Author(s):

Disa L. Hammarlöf ◽

Carsten Kröger ◽

Siân V. Owen ◽

Rocío Canals ◽

Lizeth Lacharme Lora ◽

...

Keyword(s):

Gene Expression Signature ◽

Systemic Infection ◽

Bloodstream Infections ◽

Human Infection ◽

Sub Saharan Africa ◽

Infection Model ◽

Nucleotide Polymorphisms ◽

Bacterial Survival ◽

Serovar Typhimurium ◽

Sub Saharan

Introductory ParagraphSalmonella enterica serovar Typhimurium ST313 is a relatively newly emerged sequence type that is causing a devastating epidemic of bloodstream infections across sub-Saharan Africa. Analysis of hundreds of Salmonella genomes has revealed that ST313 is closely-related to the ST19 group of S. Typhimurium that cause gastroenteritis across the world. The core genomes of ST313 and ST19 vary by just 1000 single-nucleotide polymorphisms (SNPs). We hypothesised that the phenotypic differences that distinguish African Salmonella from ST19 are caused by certain SNPs that directly modulate the transcription of virulence genes.Here we identified 3,597 transcriptional start sites (TSS) of the ST313 strain D23580, and searched for a gene expression signature linked to pathogenesis of Salmonella. We identified a SNP in the promoter of the pgtE gene that caused high expression of the PgtE virulence factor in African S. Typhimurium, increased the degradation of the factor B component of human complement, contributed to serum resistance and modulated virulence in the chicken infection model. The PgtE protease is known to mediate systemic infection in animal models. We propose that high levels of expression PgtE of by African S. Typhimurium ST313 promotes bacterial survival and bacterial dissemination during human infection.Our finding of a functional role for an extra-genic SNP shows that approaches used to deduce the evolution of virulence in bacterial pathogens should include a focus on non-coding regions of the genome.

Download Full-text