# Presentation: 037615

## Potential concerns for simian foamy virus (SFV) transmission by blood and blood products

**Hira Nakhasi, Ph.D.**
**DETTD/OBRR/CBER/FDA**
**BPAC, December 13, 2001**

## Potential concerns for simian foamy virus (SFV) transmission by blood and blood products 

**Potential concerns for simian foamy virus (SFV) transmission by blood and blood products **

**Issue: **
**FDA seeks advice on its approach to assessing the possible transfusion risk from SFV**

## Background Information

**Background Information**

**Infections in Primates**
**Simian Foamy viruses (SFV) belong to retroviridae family.**
**Prevalence of SFV infection in wild animals is high**
**Seroprevalence higher in captive vs wild animals..**
**Precise mode of transmission is not clear; transmission by saliva is indicated in animals.**
**Virus has been isolated from various organs of infected animals, but without evidence of pathology**.

## Background Information

**Background Information**

**Infections in humans**
**Some human populations in Africa harbor SFV infections**
**Humans who are occupationally exposed to non-human primates can be infected by SFV.**
**Association of several diseases in humans with SFV infection is tenuous **
**Thorough analysis resulted in failure of such an association.**

## Current Concerns

**Current Concerns**

**Unlinked CDC serosurvey of North American zoo workers identified positive workers**
**4/322 were identified as seropositive for SFV originating from chimpanzees; all 4 individuals handled non-human primates.**** **
**Seropositivity to SFV found in ~1.8-3.0% of persons occupationally exposed to non-human primates**
** ****Unlinked SFV surveillance of non-human primate handlers conducted by Health Canada found 2/46 seroreactive**
**1/46 individual serum sample tested strongly positive in SFV western blot (WB) analysis.**
**1/46 serum sample reacted weakly in SFV WB test**.

## Current Concerns.......

**Current Concerns.......**

**SFV has been isolated from human peripheral blood lymphocytes of workers exposed to non-human primates.**
**Look back study by CDC and ARC**
**4 transfused recipients who received blood components from one SFV positive donor tested negative for SFV 1.5 to 7 years post transfusion.**
**Data appear insufficient to exclude risk from transfusion**

## Topics to be discussed

**Topics to be discussed**

**A. Review of SFV biology and pathogenesis. (Arifa Khan, FDA)**
**B. Review of investigation on human infections with SFV and proposed human studies (Louisa Chapman, CDC)**
**C. Review of risk assessment (Paul Sandstrom, Health Canada)**
**D. Proposed animal study on SFV transmission by blood (Arifa Khan, FDA)**

## Questions for the Committee

**Questions for the Committee**

**1. Does the committee agree that the currently available data are insufficient to determine whether SFV can cause adverse health effects in humans?**

## Questions for the Committee cont.....

**Questions for the Committee cont.....**

**2. Does the committee agree that currently available data are insufficient to determine whether SFV can be transmitted by blood transfusion?**

## Questions for the Committee cont......

**Questions for the Committee cont......**

**3. Please comment on the adequacy of the proposed studies to evaluate SFV transmission by blood transfusion.**