Retrovirology Open Access Sivdrl Detection in Captive Mandrills: Are Mandrills Infected with a Third Strain of Simian Immunodeficiency Virus? Nucleic Acids Were Isolated from Pbmc by a Procedure Using Silica

A pol-fragment of simian immunodeficiency virus (SIV) that is highly related to SIVdrl-pol from drill monkeys (Mandrillus leucophaeus) was detected in two mandrills (Mandrillus sphinx) from Amsterdam Zoo. These captivity-born mandrills had never been in contact with drill monkeys, and were unlikely to be hybrids. Their mitochondrial haplotype suggested that they descended from founder animals in Cameroon or northern Gabon, close to the habitat of the drill. SIVdrl has once before been found in a wild-caught mandrill from the same region, indicating that mandrills are naturally infected with a SIVdrl-like virus. This suggests that mandrills are the first primate species to be infected with three strains of SIV: SIVmnd1, SIVmnd2, and SIVdrl. Findings To date over 30 strains of simian immunodeficiency virus (SIV) have been isolated from African primate species and sequenced [1]. Mandrills (Mandrillus sphinx) are quite exceptional among African monkeys in that they harbour two distinct SIV strains, designated SIVmnd1 and SIVmnd2, with a separate geographic distribution [2,3] (see also Figure 1A). SIV infections are mostly non-patho-genic in their natural hosts. SIVmnd1, despite high virus levels in chronically infected mandrills, has only a small effect on the T-cell counts, and primary infection does not induce clinical symptoms [4,5]. However, two cases of immunodeficiency were reported in mandrills after long-term (>18 years) SIV infection [6]. In 2003, a 20-year old male captive mandrill (mandrill CAS) housed at Artis Zoo (Amsterdam, The Netherlands), suffering from heart failure and poor general condition, was found to be positive for serum SIV antibodies. Inspection of the other three mandrills of his group, a ten-year old female (mandrill REB) and their offspring (mandrills RAF, 3 years old and HAB, 2 months old), showed that the female and one of the offspring (HAB) were also SIV antibody-positive. Both EDTA-plasma and PBMC (isolated with the Opti-Prep system (Nycomed, Oslo, Norway)) was obtained from the animals for further analysis. Our goal was to investigate whether the monkeys were virus carriers, and which strain of SIV they harboured. To detect both SIVmnd1 and SIVmnd2, we designed two nested primers sets based on published pol gene sequences that amplify an RT fragment of 282 nucleotides (Table 1). which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.