Search

After the large-scale outbreak of Ebola hemorrhagic fever (EHF) in Bandundu region, Democratic Republic of the Congo, a program was developed to help detect and prevent future outbreaks of EHF in the region. The long-term surveillance and prevention strategy is based on early recognition by physicians, immediate initiation of enhanced barrier-nursing practices, and the use of an immunohistochemical diagnostic test performed on formalin-fixed skin specimens of patients who die of suspected viral hemorrhagic fever. The program was implemented in September 1995 during a 4-day workshop with 28 local physicians representing 17 of 22 health zones in the region. Specimen collection kits were distributed to clinics in participating health zones, and a follow-up evaluation was conducted after 6 months. The use of a formalin-fixed skin specimen for laboratory confirmation of EHF can provide an appropriate method for EHF surveillance when linked with physician training, use of viral hemorrhagic fever isolation precautions, and follow-up investigation.

A patient with undiagnosed Ebola (EBO) hemorrhagic fever (EHF) was transferred from Kikwit to a private clinic in Kinshasa, Democratic Republic of the Congo. A diagnosis of EHF was suspected on clinical grounds and was confirmed by detection of EBO virus-specific IgM and IgG in serum of the patient. During the course of the disease, although she had no known predisposing factors, the patient developed a periorbital mucormycosis abscess on eyelid tissue that was biopsied during surgical drainage; the abscess was histologically confirmed. Presence of EBO antigen was also detected by specific immunohistochemistry on the biopsied tissue. The patient survived the EBO infection but had severe sequelae associated with the mucormycosis. Standard barrier-nursing precautions were taken upon admission and upgraded when EHF was suspected; there was no secondary transmission of the disease.

Laboratory diagnosis of Ebola hemorrhagic fever (EHF) is currently performed by virus isolation and serology and can be done only in a few high-containment laboratories worldwide. In 1995, during the EHF outbreak in the Democratic Republic of Congo, the possibility of using immunohistochemistry (IHC) testing of formalin-fixed postmortem skin specimens was investigated as an alternative diagnostic method for EHF. Fourteen of 19 cases of suspected EHF met the surveillance definition for EHF and were positive by IHC. IHC, serologic, and virus isolation results were concordant for all EHF and non-EHF cases. IHC and electron microscopic examination showed that endothelial cells, mononuclear phagocytes, and hepatocytes are main targets of infection, and IHC showed an association of cellular damage with viral infection. The finding of abundant viral antigens and particles in the skin of EHF patients suggests an epidemiologic role for contact transmission. IHC testing of formalin-fixed skin specimens is a safe, sensitive, and specific method for laboratory diagnosis of EHF and should be useful for EHF surveillance and prevention.