scholarly journals African Swine Fever Virus (ASFV): Biology, Genomics and Genotypes Circulating in Sub-Saharan Africa

Viruses ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2285
Author(s):  
Emma P. Njau ◽  
Eunice M. Machuka ◽  
Sarah Cleaveland ◽  
Gabriel M. Shirima ◽  
Lughano J. Kusiluka ◽  
...  
Keyword(s):  
Vaccine Development ◽  
African Swine Fever Virus ◽  
Control Strategies ◽  
African Swine Fever ◽  
Sub Saharan Africa ◽  
Pork Products ◽  
Sub Saharan ◽  
Haemorrhagic Disease ◽  
And Control ◽  
The 19Th Century

African swine fever (ASF) is a highly infectious and fatal haemorrhagic disease of pigs that is caused by a complex DNA virus of the genus Asfivirus and Asfarviridae African suids family. The disease is among the most devastating pig diseases worldwide including Africa. Although the disease was first reported in the 19th century, it has continued to spread in Africa and other parts of the world. Globally, the rising demand for pork and concomitant increase in transboundary movements of pigs and pork products is likely to increase the risk of transmission and spread of ASF and pose a major challenge to the pig industry. Different genotypes of the ASF virus (ASFV) with varying virulence have been associated with different outbreaks in several countries in sub-Saharan Africa (SSA) and worldwide, and understanding genotype circulation will be important for ASF prevention and control strategies. ASFV genotypes unique to Africa have also been reported in SSA. This review briefly recounts the biology, genomics and genotyping of ASFV and provides an account of the different genotypes circulating in SSA. The review also highlights prevention, control and progress on vaccine development and identifies gaps in knowledge of ASFV genotype circulation in SSA that need to be addressed.

scholarly journals Live Attenuated African Swine Fever Viruses as Ideal Tools to Dissect the Mechanisms Involved in Cross-Protection

Viruses ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 1474
Author(s):  
Elisabeth Lopez ◽  
Juanita van Heerden ◽  
Laia Bosch-Camós ◽  
Francesc Accensi ◽  
Maria Jesus Navas ◽  
...  
Keyword(s):  
Vaccine Development ◽  
African Swine Fever Virus ◽  
Virulent Strain ◽  
Sequence Similarity ◽  
Clinical Signs ◽  
African Swine Fever ◽  
Cross Protection ◽  
Sub Saharan Africa ◽  
Genotype I ◽  
Genotype Ii

African swine fever (ASF) has become the major threat for the global swine industry. Furthermore, the epidemiological situation of African swine fever virus (ASFV) in some endemic regions of Sub-Saharan Africa is worse than ever, with multiple virus strains and genotypes currently circulating in a given area. Despite the recent advances on ASF vaccine development, there are no commercial vaccines yet, and most of the promising vaccine prototypes available today have been specifically designed to fight the genotype II strains currently circulating in Europe, Asia, and Oceania. Previous results from our laboratory have demonstrated the ability of BA71∆CD2, a recombinant LAV lacking CD2v, to confer protection against homologous (BA71) and heterologous genotype I (E75) and genotype II (Georgia2007/01) ASFV strains, both belonging to same clade (clade C). Here, we extend these results using BA71∆CD2 as a tool trying to understand ASFV cross-protection, using phylogenetically distant ASFV strains. We first observed that five out of six (83.3%) of the pigs immunized once with 106 PFU of BA71∆CD2 survived the tick-bite challenge using Ornithodoros sp. soft ticks naturally infected with RSA/11/2017 strain (genotype XIX, clade D). Second, only two out of six (33.3%) survived the challenge with Ken06.Bus (genotype IX, clade A), which is phylogenetically more distant to BA71∆CD2 than the RSA/11/2017 strain. On the other hand, homologous prime-boosting with BA71∆CD2 only improved the survival rate to 50% after Ken06.Bus challenge, all suffering mild ASF-compatible clinical signs, while 100% of the pigs immunized with BA71∆CD2 and boosted with the parental BA71 virulent strain survived the lethal challenge with Ken06.Bus, without almost no clinical signs of the disease. Our results confirm that cross-protection is a multifactorial phenomenon that not only depends on sequence similarity. We believe that understanding this complex phenomenon will be useful for designing future vaccines for ASF-endemic areas.

scholarly journals Research on Invasive Nontyphoidal Salmonella Disease and Developments Towards Better Understanding of Epidemiology, Management, and Control Strategies

2020 ◽  
Vol 71 (Supplement_2) ◽  
pp. S127-S129
Author(s):  
Samuel Kariuki ◽  
Ellis Owusu-Dabo
Keyword(s):  
Burden Of Illness ◽  
Control Strategies ◽  
Sub Saharan Africa ◽  
Disease Entity ◽  
Middle Income ◽  
Diagnostic Strategies ◽  
Disease Epidemiology ◽  
Middle Income Countries ◽  
Sub Saharan ◽  
And Control

Abstract During the 11th International Conference on Typhoid and Other Invasive Salmonelloses held in Hanoi, Vietnam, a number of papers were presented on the burden of disease, epidemiology, genomics, management, and control strategies for invasive nontyphoidal Salmonella (iNTS) disease, which is increasingly becoming an important public health threat in low- and middle-income countries, but especially in sub-Saharan Africa (sSA). Although there were minor variations in characteristics of iNTS in different settings (urban vs rural, country to country), it was observed that iNTS has gained greater recognition as a major disease entity in children younger than 5 years. Renewed efforts towards greater understanding of the burden of illness, detection and diagnostic strategies, and management and control of the disease in communities in sSA through the introduction of vaccines will be important.

scholarly journals Review of African swine fever : transmission, spread and control : review article

2009 ◽  
Vol 80 (2) ◽  
Author(s):  
M-L. Penrith ◽  
W. Vosloo
Keyword(s):  
Western Europe ◽  
New Technology ◽  
African Swine Fever ◽  
Sub Saharan Africa ◽  
The Caucasus ◽  
Susceptible Host ◽  
Sub Saharan ◽  
And Control ◽  
Free Ranging ◽  
Pig Husbandry

African swine fever is one of the most important and serious diseases of domestic pigs. Its highly contagious nature and ability to spread over long distances make it one of the most feared diseases, since its devastating effects on pig production have been experienced not only in most of sub-Saharan Africa but also in western Europe, the Caribbean, Brazil and, most recently, the Caucasus. Unlike most diseases of livestock, there is no vaccine, and therefore prevention relies entirely upon preventing contact between the virus and the susceptible host. In order to do so it is necessary to understand the way in which the virus is transmitted and spreads. By implementing strict biosecurity measures that place barriers between the source of virus and the pigs it is possible to prevent infection. However, this has implications for free-ranging pig husbandry systems that are widespread in developing countries. Attempts to produce a vaccine are ongoing and new technology offers some hope for the future, but this will not remove the necessity for implementing adequate biosecurity on pig farms.

scholarly journals African swine fever virus – the possible role of flies and other insects in virus transmission

2020 ◽  
Vol 64 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Mateusz Fila ◽  
Grzegorz Woźniakowski
Keyword(s):  
African Swine Fever Virus ◽  
Animal Health ◽  
Virus Transmission ◽  
Disease Outbreaks ◽  
African Swine Fever ◽  
Disease Spread ◽  
The Baltic ◽  
Haemorrhagic Disease ◽  
And Control

AbstractAfrican swine fever (ASF) is an acute viral haemorrhagic disease of pigs and wild boars. It presents a serious threat to pig production worldwide, and since 2007, ASF outbreaks have been recorded in the Caucasus, Eastern Europe, and the Baltic States. In 2014, the disease was detected in Poland. ASF is on the list of notifiable diseases of the World Organisation for Animal Health (OIE). Due to the lack of an available vaccine and treatment, the countermeasures against the disease consist in early detection of the virus in the pig population and control of its spread through the elimination of herds affected by disease outbreaks. Knowledge of the potential vectors of the virus and its persistence in the environment is crucial to prevent further disease spread and to understand the new epidemiology for how it compares to the previous experience in Spain gathered in the 1970s and 1980s.

scholarly journals Risk Analysis of the Transmission Route for the African Swine Fever Virus in Mainland China

2021 ◽  
Vol 9 ◽  
Author(s):  
Jiang-Hong Hu ◽  
Xin Pei ◽  
Gui-Quan Sun ◽  
Zhen Jin
Keyword(s):  
African Swine Fever Virus ◽  
Mainland China ◽  
African Swine Fever ◽  
Infection Risk ◽  
Fever Virus ◽  
Transmission Model ◽  
Transmission Route ◽  
Pork Products ◽  
Python Language ◽  
And Control

African swine fever first broke out in mainland China in August 2018 and has caused a substantial loss to China’s pig industry. Numerous investigations have confirmed that trades and movements of infected pigs and pork products, feeding pigs with contaminative swills, employees, and vehicles carrying the virus are the main transmission routes of the African swine fever virus (ASFV) in mainland China. However, which transmission route is more risky and what is the specific transmission map are still not clear enough. In this study, we crawl the data related to pig farms and slaughterhouses from Baidu Map by writing the Python language and then construct the pig transport network. Following this, we establish an ASFV transmission model over the network based on probabilistic discrete-time Markov chains. Furthermore, we propose spatiotemporal backward detection and forward transmission algorithms in semi-directed weighted networks. Through the simulation and calculation, the risk of transmission routes is analyzed, and the results reveal that the infection risk for employees and vehicles with the virus is the highest, followed by contaminative swills, and the transportation of pigs and pork products is the lowest; the most likely transmission map is deduced, and it is found that ASFV spreads from northeast China to southwest China and then to west; in addition, the infection risk in each province at different times is assessed, which can provide effective suggestions for the prevention and control of ASFV.

Pathogenesis of African swine fever virus inOrnithodorosticks

2001 ◽  
Vol 2 (2) ◽  
pp. 121-128 ◽  
Author(s):  
Steven B. Kleiboeker ◽  
Glen A. Scoles
Keyword(s):  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus ◽  
Sub Saharan Africa ◽  
Hemorrhagic Disease ◽  
Sylvatic Cycle ◽  
Infectious Dose ◽  
Domestic Pigs ◽  
Ornithodoros Porcinus Porcinus ◽  
Sub Saharan

AbstractAfrican swine fever virus (ASFV) is the only known DNA arbovirus and the sole member of the family Asfarviridae. It causes a lethal, hemorrhagic disease in domestic pigs. ASFV is enzootic in sub-Saharan Africa and is maintained in a sylvatic cycle by infecting both wild members of the Suidae (e.g. warthogs) and the argasid tickOrnithodoros porcinus porcinus. The pathogenesis of ASFV inO. porcinus porcinusticks is characterized by a low infectious dose, lifelong infection, efficient transmission to both pigs and ticks, and low mortality until after the first oviposition. ASFV pathogenesis in warthogs is characterized by an inapparent infection with transient, low viremic titers. ThusO. porcinus porcinusticks probably constitute the most important natural vector of ASFV, although both the mammalian and tick hosts are probably required for the maintenance of ASFV in the sylvatic cycle. The mechanism of ASFV transmission from the sylvatic cycle to domestic pigs is probably through infected ticks feeding on pigs. In addition toO. porcinus porcinus, a number of North American, Central American and Caribbean species ofOrnithodoroshave been shown to be potential vectors of ASFV.

scholarly journals Co-Circulation of Multiple Serotypes of Bluetongue Virus in Zambia

Viruses ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 963
Author(s):  
Herman M. Chambaro ◽  
Michihito Sasaki ◽  
Edgar Simulundu ◽  
Isaac Silwamba ◽  
Yona Sinkala ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Bluetongue Virus ◽  
Prevention And Control ◽  
Control Strategies ◽  
Viral Disease ◽  
Sub Saharan Africa ◽  
High Seroprevalence ◽  
Economic Implications ◽  
Sub Saharan ◽  
And Control

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.

scholarly journals Nontyphoidal Salmonella among Children under 5 Years Old in Sub-Saharan Africa and South Asia in the Global Enteric Multicenter Study

2021 ◽  
Author(s):  
Rina Das ◽  
Md. Ahshanul Haque ◽  
Mohammod Jobayer Chisti ◽  
Tahmeed Ahmed ◽  
Abu Syed Golam Faruque
Keyword(s):  
South Asia ◽  
Multicenter Study ◽  
Control Strategies ◽  
Sub Saharan Africa ◽  
Severe Diarrhea ◽  
Asymptomatic Children ◽  
Toilet Facility ◽  
Sub Saharan ◽  
And Control ◽  
Children Under 5

Factors associated with nontyphoidal Salmonella (NTS) infection have not been well characterized to date. We aimed to compare the associated factors among children under age 5 years with NTS infection in sub-Saharan Africa and South Asia. Data from children having moderate-to-severe diarrhea (MSD) and asymptomatic children with NTS isolated from fecal specimens were extracted from the Global Enteric Multicenter Study (GEMS), conducted from December 2007 to March 2011. Compared with NTS-negative children, NTS-associated MSD cases in South Asia were associated with the presence of goat in the house (adjusted odds ratio [aOR]: 2.15; 95% confidence interval [CI]: 1.25–3.70) and handwashing after handling an animal (aOR: 2.26; 95% CI: 1.36–3.74). In sub-Saharan Africa, children with NTS associated MSD had a greater association with stunting (1.21 95% CI: 1.01–1.45), longer duration of diarrhea (aOR: 1.25 95% CI: 1.19–1.31); presence of cow in house (aOR: 1.54 95% CI: 1.09–2.16), handwashing after handling animal (aOR: 2.41 95% CI: 1.74–3.33). Drinking tube well water (aOR: 0.54 95% CI: 0.32–0.91), availability of toilet facility (aOR: 0.58 95% CI: 0.53–0.65), and handwashing before eating (aOR: 0.76 95% CI: 0.57–1.00) and after defecation (aOR: 0.80 95% CI: 0.69, 0.94) were found to be protective. The differentials between children of both regions having fecal NTS are distinct and underscore the need for policymaking for preventive and control strategies targeting stunted children.

scholarly journals Development of Diagnostic Tests Provides Technical Support for the Control of African Swine Fever

Vaccines ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 343
Author(s):  
Zilong Qiu ◽  
Zhaoyao Li ◽  
Quanhui Yan ◽  
Yuwan Li ◽  
Wenjie Xiong ◽  
...  
Keyword(s):  
Early Detection ◽  
African Swine Fever Virus ◽  
Control Strategies ◽  
African Swine Fever ◽  
Laboratory Diagnosis ◽  
Rapid Identification ◽  
Diagnostic Methods ◽  
Clinical Test ◽  
Pork Production ◽  
And Control

African swine fever is a highly contagious global disease caused by the African swine fever virus. Since African swine fever (ASF) was introduced to Georgia in 2007, it has spread to many Eurasian countries at an extremely fast speed. It has recently spread to China and other major pig-producing countries in southeast Asia, threatening global pork production and food security. As there is no available vaccine at present, prevention and control must be carried out based on early detection and strict biosecurity measures. Early detection should be based on the rapid identification of the disease on the spot, followed by laboratory diagnosis, which is essential for disease control. In this review, we introduced the prevalence, transmission routes, eradication control strategies, and diagnostic methods of ASF. We reviewed the various methods of diagnosing ASF, focusing on their technical characteristics and clinical test results. Finally, we give some prospects for improving the diagnosis strategy in the future.

scholarly journals EPIZOOTIOLOGICAL SITUATION OF АFRICAN SWINE FEVER IN EUROPE

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.

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