Abstract

In November 2017, at the Taricaya Rescue Centre (TRC), a 1–2-year-old, confiscated, black spider monkey (Ateles chamek) presented with cold sore-like symptoms. A second young black spider monkey, which was a cage-mate, presented with the same herpes-like symptoms in January 2018. Both monkeys were part of a reintroduction program of black spider monkeys into the Tambopata National Reserve, south of the Madre de Dios River in Peru, where the natural population of black spider monkeys has totally vanished due to bushmeat hunting and illegal pet trafficking.

Both monkeys survived, and blood was taken at the TRC and shipped on Whatman paper filters (GE Healthcare Bio-Sciences Corp., Westborough, MA, USA) to the Biomedical Primate Research Centre (BPRC) to screen their viral status. At the BPRC, antibodies and DNA were isolated from the filters and used in both an in-house-developed enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR), respectively. ELISA data from the sera from the first bleeding, November 2017, revealed that both spider monkeys were negative (or had no cross-reacting antibodies) for various human viral infection including human herpes virus 1 (HHV1), also called herpes simplex virus 1.

To rule out a recent primary HHV1 infection, PCR was performed on the whole blood from November 2017, and most interesting this PCR, followed by subsequent sequence analysis, revealed a HHV1 infection in the first monkey. Both animals had been kept as pets with limited exposure to the direct environment, except via their owners. Therefore, we concluded that HHV1 was probably acquired from close contact with the owners of the first monkey and passed on to the second monkey via natural oral contact during the first months together. Primates with an active HHV1 infection reveal gingivitis and oral ulcers, which usually transform to latent infection in the nervous system with no or intermittent manifestation and virus production. In general, in New World monkeys (NWMs), HHV1 is considered to be fatal.^1-3

ELISA results from both monkeys were compared with historical data from 35 black spider monkey samples from several European zoos and South American non-human primate rehabilitation centres.

None of the historical data revealed any positive antibody results to HHV1, but we found one black spider monkey with a positive HHV1 PCR at the TRC. Upon request in March and April 2018, new sets of sera and blood were sent to the BPRC to re-screen the black spiders from the TRC. Trading pet monkeys is prohibited in Peru; however, especially NWMs like marmosets (Callithrix spp.), squirrel monkeys (Saimiri spp.) and spider monkeys (Ateles spp.) can be purchased via illegal pet trafficking inside the country. For HHV1, the clinical manifestations and outcome in marmosets are quite acute and lethal, but monkeys with a latent HHV1 infection could be a serious concern for future reintroduction programs of NWMs back into the Amazon forest, so the two monkeys presented here will never be a part of future reintroduction programs. Previous repeated negative screening of three groups of black spider monkeys allowed their release into the Tambopata National Reserve, and frequent tracking of the released animals and optical screening for herpes infections will be part of all reintroduction programs.

Literature Cited

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2.  Matz-Rensing K, Jentsch KD, Rensing S, Langenhuijzen S, Verschoor E, Niphuis H, Kaup FJ. Fatal herpes simplex infection in a group of common marmosets (Callithrix jacchus). Vet Pathol. 2003;40:405–411.

3.  Schrenzel MD, Osborn KG, Shima A. Naturally occurring fatal Herpes simplex virus 1 infection in a family of white-faced saki monkeys (Pithecia pithecia pithecia). J Med Primatol. 2003;32:7–14.