PLASMAPHERESIS MEASURES IN SUDAN
D.I.H. SIMPSON, J. KNOBLOCH, C.C. DRAPER, J. BLAGDON
London School of Hygiene and Tropical Medicine, Keppel Street (Gower Street), London WC1E 7HT, England.
During investigations on the Ebola outbreak in Southern Sudan during the hight of the epidepic, it was felt necessary to start collecting immune plasma from patients who had recovered from the disease. Patients for consideration were selected on clinical grounds alone as there were no serological facilities available to examine the antibody status of each patient. Plasmapheresis measures were extremely limited because there were no supplies of electricity and in any case no centrifuge was available and refrigeration facilities were inadequate.
During the epidemic period in October and November 1976, 51 convalescent patients were bled for immune plasma in Nzara and Maridi, 500 ml of whole blood was removed from each patient using Traverol transfusion equipment and Mixed with acid-citrate dextrose solution. Each aliquot was then allowed to settle by gravity alone for a period of 3 hours. Plasma was then removed and red cells were returned to the patients' circulation.
Each aliquot of plasma was frozen as quickly as possible at -10ºC before being transhipped either to the United Kingdom or Germany for testing. Ten of the 51 aliquots were negative for Ebola antibody by immunofluorescent testing but the remaining 41 samples contained antibody at levels varying from 1/8 to 1/256.
A second WHO team left for the Sudan in January 1977 equipped with electricity generators, two refrigerated centrifuges and adequate -20ºC deep freeze storage space. In addition, this team carried a complete supply of plasmapheresis equipment. Within 2 weeks the second team had collected 103 units of immune plasma from convalescent patients in Maridi. All the units of plasma were transhipped by air freight to the United Kingdom where they were tested for Ebola antibodies and for Hepatitis B surface antigen and surface antibody by fluorescent antibody techniques and by radio-immuno assay respectively. Twenty three units of plasma contained no detectable Ebola virus antibody, 12 had antibody levels of 1:4; 33 levels of 1:8; 17 levels of 1:16; and 18 had antibody levels 1:32. Seven units had detectable Hepatitis B surface antigen and 20 had evidence of Hepatitis B surface antibody.