A review of the recent advances on Lassa fever with special reference to molecular epidemiology and progress in vaccine development

1Medugu, N., *1Adegboro, B., 2Babazhitsu, M. S., 3Kadiri, M., and 4Abanida, E. A.

1Departments of Medical Microbiology and Immunology, Nile University of Nigeria, Abuja, Nigeria

2Department of Medical Microbiology and Parasitology, Faculty of Basic Clinical Sciences, College of Health Sciences, Usmanu Danfodiyo University, Sokoto, Nigeria

3Department of Medical Microbiology and Parasitology, University of Ilorin Teaching Hospital, Ilorin, Nigeria 4Epidemiology Unit, World Health Organization, Harare, Zimbabwe                                             

*Correspondence to: boazadegboro@gmail.com

Abstract:

Lassa fever, a viral hemorrhagic fever caused by the Lassa virus (LASV), is endemic in West Africa and is associated with high morbidity and mortality. At least three of the four proposed seven lineages of LASV are found in Nigeria, where the multimammate rat, Mastomys natalensis, serves as the primary reservoir. Endemic countries report approximately 200,000 infections and 5,000 deaths annually, with Nigeria experiencing thousands of infections and hundreds of deaths including healthcare workers. The aim of this review is to provide scientific information for better understanding of the evolutionary biology, molecular epidemiology, pathogenesis, diagnosis, and prevention of Lassa fever in Nigeria and other endemic regions worldwide, which can lead to improved control efforts and reduce morbidity and mortality from recurrent epidemics. To achieve this aim, observational studies such as case series, cross-sectional and cohort studies published between December 2017 and September 2022 were searched for on various online databases including Google Scholar, Africa Journals Online (AJOL), Research Gates, PubMed, PMIC, NCDC, and WHO websites. Although the origin and evolutionary history, and the transmission dynamics of Lassa virus have been revealed through recent molecular epidemiological studies, the factors that drive the evolution of the virus remain unclear. Genetic changes in the viral genome may have enabled the virus to adapt to humans. Diagnosis of Lassa fever has also advanced from basic serological tests to more sophisticated methods such as quantitative real time polymerase chain reaction (qRT-PCR) and sequencing, which are particularly useful for identifying outbreak strains. Several vaccines, including recombinant vesicular stomatitis virus (rVSV), virus-like particle (VLP), and DNA-based vaccines, have shown promise in animal models and some have progressed to phase 2 clinical trials. Preventing and controlling Lassa fever is critical to safeguard the health and well-being of affected communities. Effective measures such as rodent control, improved sanitation, and early detection and isolation of infected individuals are essential for reducing transmission. Ongoing research into the genetic and ecological factors that drive the evolution of Lassa virus is necessary to reduce the impacts of Lassa fever. Continue reading “A review of the recent advances on Lassa fever with special reference to molecular epidemiology and progress in vaccine development”

A review of COVID-19 vaccines strategies and anti-vaxxers theories

*1Adesokan, A., and 2Obeid, M. A.

1PreciseMed, Glasgow, United Kingdom                                 

2Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmacy, Yarmouk University Irbid, Jordan

*Correspondence to: Ade@precisemed.co.uk; dapoadesokan@gmail.com

Abstract:

In what is a global record time of getting the COVID-19 vaccines available within 11 months, the world has equally been faced with several myths and conspiracy theories dissuading the public from accepting vaccination as an important measure in the response to the pandemic. We reviewed the leading conspiracy theories and balanced these with the scientific basis of viral transmission and replication and the broad role of vaccination in tackling this challenge. We briefly examined the design of the leading vaccines, and provided recommendations for worldwide COVID-19 distribution, acceptance and use. Continue reading “A review of COVID-19 vaccines strategies and anti-vaxxers theories”

Production and efficacy testing of live attenuated and inactivated vaccines against experimental Salmonella Kentucky infection in broiler chickens

*1Igomu, E. E., 2Fagbamila, I. O., 3Elayoni, E. E., 1Pwajok, D., 1Agu, G. C., 4Govwang, P. F., 5Msheliza, E. G., 5Oguche, M. O., and 6Mamman, P. H.

*1Bacterial Vaccine Production Division, National Veterinary Research Institute, P.M.B. 01, Vom, Nigeria

2Bacterial Research Division, National Veterinary Research Institute, Vom, Nigeria

3Biological Science Department, Adamawa State University Mubi, Adamawa State, Nigeria

4Livestock Investigation Division, National Veterinary Research Institute, Vom, Nigeria

5Central Diagnostic Division, National Veterinary Research Institute, Vom, Nigeria 6Department of Veterinary Microbiology, Ahmadu Bello University, Zaria, Nigeria *Correspondence to: elayonigomu@gmail.com; +2348032786224

Abstract:
Background: Salmonella Kentucky is of great veterinary and public health concern and exhibits the capacities to emerge as the most prominent Salmonella serotype in human disease. The objective of this study is to evaluate the efficacy of prepared live attenuated and inactivated vaccines against experimentally induced salmonellosis caused by S. Kentucky in broiler chickens.

Methods: Field isolate of S. Kentucky was obtained from the National Veterinary Research Institute Vom, Nigeria and used in the preparation of experimental vaccines. Broiler chickens purchased and ascertained to be free of Salmonellae were randomly distributed into three experimental groups of 20 chicks each. Five-bromouracil at a concentration of 1000μg/ml was used in attenuation of S. Kentucky in preparation of the live vaccine and 0.6% formaldehyde was used in inactivation of S. Kentucky for preparation of the inactivated vaccine. Group 1 chicks were immunized with the live vaccine subcutaneously at 0.5ml per bird, group 2 received 1ml of the inactivated vaccine subcutaneously, and group 3 served as unvaccinated/control.

Results: There was 100% faecal inhibition and 100% vaccinal efficacy in broiler chickens immunized with the live vaccine on day 56 of age, and 49.6% faecal inhibition and 82.8% vaccinal efficacy in broiler chickens immunized with the inactivated vaccine on day 56 of age when compared with the unvaccinated control. The vaccinated birds also showed higher antibody (IgY) titre levels from day 21 to day 56 of age (p<0.001) on all sampling days when values were compared with the unvaccinated birds.

Conclusion: The interplay between vaccination protocol that includes administration of live attenuated or inactivated S. Kentucky vaccines and developed antibody (IgY) can reduce intestinal colonization by S. Kentucky and subsequent shedding of the serovar in faeces.

Keywords: Salmonella Kentucky, 5-bromouracil, IgY, Antibody, Vaccine

Received January 9, 2019; Revised April 11, 2020; Accepted April 12, 2020

Copyright 2020 AJCEM Open Access. This article is licensed and distributed under the terms of the Creative Commons Attrition 4.0 International License <a rel=”license” href=”//creativecommons.org/licenses/by/4.0/”, which permits unrestricted use, distribution and reproduction in any medium, provided credit is given to the original author(s) and the source.

Production et tests d’efficacité de vaccins vivants atténués et inactivés contre une infection expérimentale à Salmonella Kentucky chez des poulets de chair

*1Igomu, E. E., 2Fagbamila, I. O., 3Elayoni, E. E., 1Pwajok, D., 1Agu, G.C., 4Govwang, P. F., 5Msheliza, E. G., 5Oguche, M. O., et 6Mamman, P. H. Continue reading “Production and efficacy testing of live attenuated and inactivated vaccines against experimental Salmonella Kentucky infection in broiler chickens”

Review Article: Vaccine for Malaria – How Far?

GO Oyeyinka

 

Abstract

This is a review of the progress made so far in the effort to produce a malaria vaccine. The problems that have made it impossible to get an effective vaccine for malaria are discussed. Also examined are the current efforts to produce the vaccine and the prospects for an effective vaccine in the future.
Key words: Vaccine, malaria, review.

Afr. J. Clin. Exper. Microbiol. 2005; 6(2): 139-143