Ugandan forest where Zika hides
As we walk down the winding path through dense jungle Gerald Mukisa noisily kicks up dry leaves to give warning of our approach, noting that the hot late afternoon is "snake time".
The forest is calm. Only the sound of insects, birdsong and the rustle of monkeys in the canopy above disturb the air.
It was here in the thick woodland of Zika forest, 25km from Uganda's capital, Kampala, that the mosquito-borne Zika virus was discovered in 1947.
The virus, linked to a surge in birth defects, is "spreading explosively", World Health Organisation chief Margaret Chan said this week. An emergency meeting on the outbreak is due today.
Mukisa, a guard in the forest for seven years, found out about the virus that takes its name from the woodland only two weeks ago.
"A few people who live nearby the forest and have heard about the disease are getting worried," he said. "Many others don't know about it."
Only days ago, the Zika forest was a little-known reserve visited by few other than bird watchers and scientists.
"Students come every week from all over the world," said Mukisa proudly showing off a guest book with signatures and comments by visitors from the US, Canada, France and Germany. "There are so many types of tree, and all sorts of birds."
Most local cases of the virus were mild, resulting in a rash, fever, and red eyes. Global health authorities barely took notice until an outbreak on the Micronesian island of Yap in 2007.
An outbreak in Brazil last year has been blamed for a surge in birth defects, with thousands of babies born with small heads, an incurable and sometimes fatal condition known as microcephaly.
Uganda's health ministry is keen to point out that there have been no known cases of the disease in that country, and that the outbreak in the Americas did not originate in East Africa.
"We have not recorded a case in Uganda in several years," the ministry said. "Our disease and epidemic response systems are strong, as evidenced in the way we have handled past viral haemorrhagic fever outbreaks."
Uganda has suffered outbreaks of Ebola in the past, as well as of a mysterious illness known as "nodding disease".
Today, the forest, close to the main highway from Entebbe international airport, near Kampala, is a research site for the Uganda Virus Research Institute, an environmental health and protection agency founded in 1936.
"Warning! Uganda Virus Research Institute Land. Don't Trespass", reads a metal sign.
Ruth Mirembe, 24, who lives nearby, said she was not worried after learning about the virus on Facebook.
Also spelt Ziika, the 12ha site which has more than 60 types of mosquito, means "overgrown" in the local language, Luganda.
The details of the virus's discovery, written up in a 1952 paper by Britain's Royal Society of Tropical Medicine and Hygiene, described the "forested area called Zika", where scientists were researching yellow fever among small rhesus macaque monkeys.
"This area of forest consists of a narrow, dense belt of high but broken canopy with clumps of large trees," the paper read. "It lies along the edge of a long arm of Lake Victoria, from which it is separated by a papyrus swamp."
The institute's top scientist, Julius Lutwama, described how caged monkeys had been placed at different heights, with a 36m steel tower allowing researchers to carry out studies.
"Blood samples would be taken from these monkeys to try to diagnose yellow fever but that is how Zika was found," he said.
There is no vaccine against Zika, which has spread to over 24 countries in the Americas.