Avian Influenza Outbreak in Zimbabwe

Avian Influenza Outbreak in Zimbabwe


Location: Lanark Poultry Breeding Farm on the outskirts of Harare

Latitude:              18.0912723

Longitude:          30.9216241


Highly Pathogenic Avian Influenza H5N8 was detected, for the first time in Zimbabwe, on 24 May 2017 at Larnark farm in Seke District, Mashonaland East Province. The farm is located about 30 kilometres south of the capital city, Harare, and belongs to vertically integrated poultry company, Irvine’s Zimbabwe PVT (LTD). The company is a registered bio-secure compartment, with a set up complying with OIE TAH code guidelines on


compartmentalisation. The company is involved in the production and marketing of both broiler and layer chickens.  It operates from three distinct locations namely Larnark farm, Derbyshire farm and Waterfalls farm, which are supported by 22 contract growers within a 70km radius.  Each of the three farms is subdivided into independent management units operating specific segments of the vertically integrated production system. The outbreak affected only one of the three farms, namely Larnark farm.

The company veterinarian reported to Department of Veterinary Services a sharp rise in the mortality rates in one of their Cobb 500 broiler parent flock at Lanark Farm on 24 May 2017. High mortalities were first seen at one of the broiler parent breeding unit, which had a total of 83 000 birds.  The upsurge in mortalities was initially noticed on the 17th of May 2017 and by the 24th of May a total of 3 045 birds had died at the unit. The company had administered both oral and injectable oxytetracycline to attempt to treat the birds but mortalities continued to surge.

On receiving the report on the 24th of May DVS vets immediately visited the farm to conduct investigations and observed that sick birds exhibited respiratory distress,  facial oedema and had swollen wattles. A Post-mortem examination was conducted which revealed severe peritonitis, splenomegaly with the spleen showing haemorrhagic areas together with whitish foci and congested, oedematous lungs. 2800 birds subsequently died on the 25th of May and another       2 000 birds died on the 26th of May, bringing the total number of dead birds at 7 845 out of the 83 000 bird flock by the 26th of May 2017.

Ten pooled tissue samples were collected on FTA cards for PCR. Two FTA cards were submitted to the local Central Veterinary Lab while eight were sent to the Onderstepoort Veterinary Institute (OVI) in South Africa. An additional 230 serum samples were collected and sent to the local Central Veterinary laboratory (CVL) in Harare for serological testing and the results obtained were as follows:

  • All 2 FTA cards that were sent to the local CVL tested positive for H5 Avian Influenza on RT-PCR. The local CVL does not have capacity for determining the N type
  • 183 out of 187 serum samples submitted to the CVL in Harare tested positive for H5 Avian Influenza.
  • All 8 FTA cards that were sent to South Africa tested positive for H5 Avian Influenza on RT-PCR. Sequencing test on 3 of the samples tested positive for N8
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