Wear face-masks to avoid transmission of viral and bacterial diseases to primates

Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 2
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How is the evidence assessed?

Effectiveness

50%
Certainty

5%
Harms

0%

Calculating overall effectiveness category

Background information and definitions

This intervention aims to prevent the spread of viral and bacterial diseases from humans to primates and may be especially important in situations where humans come into close contact with primates. Examples include researchers and tourists that observe habituated primates in their natural habitat, but also management/research staff involved in primate translocations, captive breeding, etc.

Other means of preventing the spread of bacterial and viral diseases from researchers/tourists/managers to primates are discussed under ‘Keep safety distance to habituated animals’, ‘Limit time that researchers/tourists are allowed to spend with habituated animals’, ‘Implement quarantine for people arriving at, and leaving the site’, ‘Ensure that researchers/tourists are up-to-date with vaccinations and healthy’, ‘Regularly disinfect clothes, boots etc.’, and ‘Wear gloves when handling primate food, tool items, etc.’.

Study locations

Key messages

One study in Uganda found that a confiscated young chimpanzee was reunited with its mother after being handled by caretakers wearing face-masks, alongside other interventions.
One before-and-after study in Rwanda, Uganda and the Democratic Republic of Congo found that numbers of mountain gorillas increased by 168% over 41 years while being visited by researchers and visitors wearing face-masks, alongside other interventions.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

A study in 2009 in savanna-woodland mosaic in Niokolo-Koba National Park, Senegal found that a confiscated 9-months old female infant chimpanzee Pan troglodytes verus that was handled by caretakers wearing face-masks along with other interventions, was reunited with its mother in the wild. Four days after confiscation, the chimpanzee was released in the vicinity of its natal group, which retrieved it immediately. The author wore a surgical mask and sanitized her hands when handling the infant and its food to prevent disease transmission. The infant’s natal group was located with the aid of poachers, after which it was released close to the group. The infant was also treated for its injured eye. The study does not distinguish between the effects of the different interventions mentioned above.
Study and other actions tested
Referenced paper
Pruetz J.D. & Kante D. (2010) Successful return of a wild infant chimpanzee (Pan troglodytes verus) to its natal group after capture by poachers. African Primates, 7, 35-41.
A controlled, before-and-after study in 1967-2008 in tropical moist montane forest in Volcanoes-, Mgahinga-, and Virunga National Parks in Rwanda, Uganda, and the Democratic Republic of Congo found that the mountain gorilla Gorilla beringei beringei population that was regularly visited by tourists and researchers that wore face-masks to avoid disease transmission along with ten other interventions, increased in size over time. Annual population growth was 4.1%, resulting in an overall population increase of 168% over 41 years. No statistical tests were carried out to determine whether this increase was significant. All visitors/researchers were recommended to wear N95 masks (when available) or a surgical mask when visiting the gorillas. Gorillas were habituated to human presence as part of the ecotourism and research programmes and visitors/researchers had to follow strict health procedures; these included keeping a safety distance to the gorillas, spending only a limited amount of time with gorilla groups, ensuring that visitors/researchers were healthy, and disinfecting visitor’s/researcher’s clothes, boots etc. In addition, the population was continuously monitored by vets and gorillas received medical treatment if necessary. When gorillas died, their cause of death was clinically determined. The study does not distinguish between the effects of the different interventions mentioned above.
Study and other actions tested
Referenced paper
Robbins M.M., Gray M., Fawcett K.A., Nutter F.B., Uwingeli P., Mburanumwe I., Kagoda E., Basabose A., Stoinski T.S., Cranfield M.R. & Byamukama J. (2011) Extreme conservation leads to recovery of the Virunga mountain gorillas. PLoS ONE, 6.

Please cite as:

Junker, J., Kühl, H.S., Orth, L., Smith, R.K., Petrovan, S.O. & Sutherland, W.J. (2020) Primate Conservation. Pages 431-482 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

This Action forms part of the Action Synopsis:

Primate Conservation

Related Actions

Actions	Effectiveness	Studies	Category
Avoid contact between wild primates and human-raised primates Action Link	No evidence found (no assessment)	0	Synopsis Link
Preventative vaccination of habituated or wild primates Action Link	Trade-off between benefit and harms	4	Synopsis Link
Wear face-masks to avoid transmission of viral and bacterial diseases to primates Action Link	Unknown effectiveness (limited evidence)	2	Synopsis Link