African swine fever

African swine fever
Ben Clark, Plum Island Animal Disease Center, Department of Homeland Security · Public domain · source
Name	African swine fever
Disease	Hemorrhagic fever of suids
Pathogen	Asfivirus
Vectors	Soft ticks (Ornithodoros)
Hosts	Domestic pigs, wild boar
Onset	Acute to chronic
Mortality	Up to 100% in acute forms
First reported	1921, Kenya

African swine fever is a contagious hemorrhagic viral disease affecting suids that causes high mortality in domestic pigs and wild boar. The condition was first described in eastern Africa and has since produced transcontinental outbreaks that involve complex interactions among wildlife, vectors, and livestock production systems. Responses to outbreaks mobilize national and international agencies and affect agricultural policy, trade, and food security in affected regions.

Overview

African swine fever emerged in the early 20th century with initial reports from Kenya and subsequent documentation in South Africa and other parts of East Africa. Outbreaks expanded through transcontinental movements linked to trade routes involving ports such as Lisbon, Rotterdam, and Shanghai, prompting interventions by organizations including the Food and Agriculture Organization and the World Organisation for Animal Health. Control efforts often engage national ministries such as the United States Department of Agriculture and the Ministry of Agriculture and Rural Development (Poland), as well as regional bodies like the European Commission and the African Union. High-profile incursions into regions including Georgia (country) and the People's Republic of China have reshaped international biosecurity strategies and veterinary surveillance networks.

Virology and Pathogenesis

The etiologic agent belongs to the family Asfarviridae and the genus Asfivirus, characterized by large double-stranded DNA genomes similar to some Poxviridae in complexity. Viral structure includes an icosahedral capsid and a multilayered envelope; key viral proteins implicated in virulence are studied by groups at institutions such as the Pasteur Institute and the Pirbright Institute. Pathogenesis involves viral tropism for mononuclear phagocytes and endothelial cells, triggering disseminated intravascular coagulation and cytokine dysregulation documented in comparative studies from laboratories at University of California, Davis and Wageningen University. Host genetics modulate disease expression, with susceptibility differences observed between breeds investigated by research programs at the National Institute of Agricultural Botany and the National Institute for Agricultural Research (INRAE).

Transmission and Epidemiology

Transmission cycles include sylvatic cycles involving soft ticks of the genus Ornithodoros in parts of Sub-Saharan Africa and domestic cycles mediated by movements of pigs and pork products along supply chains linking hubs such as Istanbul, Milan, and Hong Kong. Epidemiological investigations use molecular tracing conducted by laboratories at Centers for Disease Control and Prevention and the China Animal Health and Epidemiology Center to map introductions and spread across regions including Eastern Europe, Central Asia, and Southeast Asia. Human activities—transport via legal and illegal commerce, swill feeding practices noted in case studies from Spain and Portugal—and wildlife reservoirs like the Eurasian wild boar drive persistence, while climatic factors affecting tick ecology are modeled by teams at Imperial College London and ETH Zurich.

Clinical Signs and Diagnosis

Clinical presentations range from peracute, acute, to chronic forms; acute disease produces high fever, cutaneous erythema, and hemorrhagic lesions with mortality profiles documented in outbreak reports from Romania and Lithuania. Differential diagnosis requires exclusion of other porcine febrile illnesses investigated at diagnostic centers such as the National Veterinary Services Laboratories and the Veterinary Laboratories Agency (UK), including infections caused by agents studied in relation to Classical swine fever and Porcine reproductive and respiratory syndrome virus. Laboratory confirmation employs polymerase chain reaction assays, virus isolation in primary swine macrophages, and serology developed by consortia including the European Food Safety Authority and the International Atomic Energy Agency.

Control, Prevention, and Biosecurity

Control strategies emphasize culling, movement controls, and decontamination protocols coordinated by authorities like the Ministry of Agriculture of the People's Republic of China and national veterinary services in Poland and Spain. Biosecurity measures span farm-level interventions promoted by extension services in United States Department of Agriculture programs, border inspections at ports such as Jebel Ali, and public awareness campaigns supported by agencies including the World Bank and the United Nations Development Programme. Policies addressing compensation schemes and contingency planning involve fiscal instruments administered by treasury departments like the UK Treasury and the European Investment Bank to mitigate socioeconomic consequences.

Economic and Social Impact

Outbreaks precipitate trade restrictions imposed under frameworks administered by the World Trade Organization and affect commodity markets centered in exchanges such as the Dalian Commodity Exchange and the Chicago Mercantile Exchange. Losses to producers and disruptions to value chains have been quantified in country analyses for China, Vietnam, and Germany conducted by research teams at Institute of Agricultural Economics affiliates and university departments including Cornell University and University of São Paulo. Social effects extend to rural livelihoods in regions like Sub-Saharan Africa and Eastern Europe, triggering policy responses from development agencies including the International Monetary Fund and humanitarian branches of the European Commission.

Research and Vaccine Development

Scientific efforts to develop vaccines involve molecular approaches—live attenuated, subunit, and vectored platforms—pursued by consortia at institutions such as the Roslin Institute, National Institutes of Health, and private firms collaborating with the Bill & Melinda Gates Foundation. Challenges include immune evasion mechanisms encoded in the viral genome and safety concerns highlighted in trials overseen by regulatory bodies like the European Medicines Agency and the China Food and Drug Administration. Advances in genomics, reverse genetics, and adjuvant design from laboratories at Fred Hutchinson Cancer Research Center and Johns Hopkins University are guiding translational research and field trials in partnership with national veterinary research institutes including the Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria and the Federal Research Center for Virology and Microbiology.

Category:Swine diseases