AFRICAN SWINE FEVER

African swine fever again threatens Ghana's pig industry

After more than three years of absence, African swine fever (ASF) unfortunately reappeared in the Northern Region of Ghana in September 2002. As of December 2002, an estimated 7 061 pigs had been reported dead as a result of the disease, while an estimated 1 743 had been slaughtered and consumed by their owners. The outbreak in the Zabzugu district was probably introduced from Togo, where an outbreak is said to have occurred in Bassare, a town about 30 km from the Ghana-Togo border.

Background information
Ghana, with a human population of about 20 million, has an estimated pig population of 354 678, distributed as shown in the Table on page 10.

The prevailing pig production systems in Ghana are the free-ranging (scavenging), semi-intensive and intensive systems. Locality is a determining factor of the type of system adopted; in this case, in the affected area the majority of the pigs are reared under the semi-intensive and scavenging systems.

Introduction of ASF into Ghana
ASF has been endemic in Cameroon since 1982, in southern Senegal and Guinea-Bissau at least since the 1970s, and in Cape Verde since the 1960s. An outbreak of ASF is reported to have occurred in Nigeria in 1973. This fatal viral disease affecting pigs has become a cause for serious concern since the unexpected ASF outbreak in Côte d'Ivoire in April 1996. This was followed in 1997 by outbreaks in Benin, Nigeria and Togo, as well as increased incidence in Cape Verde.

The concern was justified by the declaration of ASF in Ghana in October 1999. Ghana had until then managed to keep out the disease in spite of the successive infection of its two close neighbours, Côte d'Ivoire and Togo. The outbreaks occurred in Greater Accra region and parts of the Volta region. Stamping-out measures were instituted to eradicate the infection, followed by intensified surveillance activities. The quarantine that had been put in place in September 1999 was lifted in October 2000. The last two outbreaks occurred in February 2000 and were rapidly investigated and stamped out; no other cases have been reported or discovered. It was estimated that about 1 000 pigs died from the outbreak and another 6 607 were destroyed. FAO made an emergency intervention through its technical cooperation programme, “Emergency assistance to eradicate African swine fever from Ghana” (contribution US$306 000), which operated from December 1999 to early 2001.

From the socio-economic study that was carried out, it was estimated that the sum of US$13 323 494 was spent in eradicating the disease. Ghana eradicated the disease very quickly and the affected areas were small and limited.

Rapid detection was facilitated by years of development of epidemiological systems with emergency preparedness through contingency planning. This was all made possible by the political support given to a strong, well-equipped and motivated veterinary service.

In the 1999 outbreak, early detection of the outbreak, when the number of affected areas was still low, and the imposition of a ban on movement of swine and meat soon after the suspicion, served to minimize the number of areas covered by the slaughter teams. This promptness of action also contributed to the successful implementation of the stamping-out exercise. In addition, the virus was very virulent, and this in itself caused a total depopulation of the affected areas before the slaughter teams reached them. A partial lifting of the ban on slaughter for large commercial farmers enabled them to reduce their stock and earn sufficient income to cover the running costs of their farms.

The establishment of an ASF diagnostic unit within the Accra Central Laboratory and the provision of staff training, equipment and other consumables made possible the implementation of serosurveillance activities. The laboratory still plays a vital and active role and has been able to carry out confirmatory diagnoses of the current outbreak.

Areas affected and measures taken following the notification
The area affected by the outbreak is situated 812 km northwest of the veterinary headquarters in Accra. There is good communication and cellular phones work in the nearest regional city, Tamale (about 650 km from Accra), which also has an airfield. The affected area is connected on the landline telephone network. The road network is good, especially up to Tamale.

The Emergency Preparedness/Early Reaction Team set up during the ASF outbreak of 1999 was still intact and was reactivated by the Director immediately after reports of pig mortality were received from the northern part of the country. This commendable action ensured the rapid diagnostic confirmation of the outbreak at the veterinary laboratory in Accra using the immunofluoresence test. The capacity of this laboratory for ASF diagnosis was enhanced during the previous ASF control project, TCP/GHA/8925, through staff training and the provision of equipment and reagents. Tissue samples were prepared for dispatch to Onderstepoort Veterinary Institute in South Africa and the United States for virus isolation and characterization, as a means of further elucidating the epidemiologic parameters of ASF in West Africa.

Control measures include a stamping-out exercise (it is estimated that about 6 000 pigs will be destroyed) and an awareness-raising campaign targeting the region's pig producers.

Animal movements and trade issues
There have been no reports of major pig movements or markets in the affected area so far. Normal activities involve small traders, mainly women, dealing in raw and cooked pork and selling this mostly during the evenings and at night in and around main towns and trading centres.

It must be pointed out that there are strong ethno-cultural ties between the peoples of Bassari district of Togo and Zabzugu-Tatale District of Ghana. The exchange of pigs and pig products is common during funerals involving people from both districts. A concerted and targeted awareness-raising campaign was organized in the affected districts by the PACE communication officer. Community opinion leaders and small-scale pig producers were actively involved in this campaign and sensitized on control measures for ASF, which is affecting their livelihood.

For more information, see: OIE Web site: http://www.oie.int/;
EMPRES Web site: http://www.fao.org/ag/AGA/AGAH/EMPRES/index.htm;
EMPRES Bulletin No. 16: http://www.fao.org/DOCREP/003/Y0482E/y0482e05.htm#l