"I feel as if my brain is burning. I haven't been able to eat for six days," says the 15-year-old farmer from a hospital bed in the Central African Republic.
Canbi is suffering severe side affects from a drug containing arsenic used to cure sleeping sickness, a disease caused by trypanosome parasites and carried by the tsetse fly.
If he survives the next three days -- a 95 percent chance -- he will be cured and return to the fields.
Sleeping sickness, which can upset the biological clock making sufferers unable to sleep at night, was almost eradicated across Africa during the colonial era.
Foreigners, motivated by the financial losses incurred when their strongest laborers and animals died, discovered a cure for the disease and ran national treatment programs.
But in countries ravaged since independence by civil war, mass migration and economic decline -- Sudan, Angola, the Democratic Republic of Congo, Uganda and parts of Central Africa -- sleeping sickness is back, sometimes in epidemic proportions.
"The disease is now the number four killer in the Central African Republic, after AIDS, malaria and polio. In some areas we are seeing entire villages decimated by sleeping sickness," said Dr August Nangouma, head of the country's sleeping sickness program.
The World Health Organization estimates half a million people suffer from sleeping sickness. It kills four in five people infected and wipes out three million livestock animals each year in some of the world's poorest countries.
In the first stage of the illness, the parasite remains in the blood and lymphatic system, causing fevers, pain and itching for several days.
After that the patient may feel fine for months or even years until the parasite reaches the central nervous system.
Then death comes soon if the disease is left untreated.
In 2001, more than 1,000 cases of people infected by the virus were recorded in Central Africa, all in rural areas, although the true figures are believed to be much higher.
Gbazigbiris in the eastern province of Haute-Mobomou, once a village of 1,000 inhabitants, is deserted. Most residents have died from sleeping sickness or moved away in fear.
Many people are also dying from the disease in the nearby town of Mboki, partly due to an influx of refugees fleeing the war in southern Sudan who bring the parasites from elsewhere.
The effects on families in rural farming communities can be devastating if one or more men become infected, stopping them working on the fields to grow food for the family.
"At a social level sufferers become stigmatized by the madness that can be a symptom of the final stage," said Dr Jose Ruiz, heading a sleeping sickness program in Mboki run by Medecins Sans Frontieres (MSF).
"Symptoms can also include, as well as disturbed sleeping patterns, a decline in intellectual capacity, uncontrollable shaking and feeling that ants are crawling under one's skin."
Catching tsetse flies in special nets can help reduce infection, as can spraying areas with insecticide -- although that is costly and often damaging to the environment.
In Zanzibar, Tanzania, scientists have tried sterilizing the tsetse fly and say that could stop the spread of the disease.
Alternatively, treating those infected can also prevent tsetse flies carrying sleeping sickness to new victims.
Six years ago in Luba, Equatorial Guinea, 15 percent of the population were infected, but since a screening and treatment program, no new cases have been reported.
Central Africans have long known about sleeping sickness, which, unlike newcomers such as AIDS, has a name in the local languages. But government money to run national treatment programs has not been forthcoming over the past decade, especially as those affected live in outlying provinces.
"Because we are far from Bangui, we receive very little help. We never get any reply to our letters of complaint so we've given up writing," said Alphonse Gbanda, mayor of Mboki.
The last time government representatives came to the province in 1996, they said they only had money to treat the few thousand Central Africans -- but not the 25,000 Sudanese refugees living in the area.
"This was pointless as everybody has to be treated for the disease to be eradicated," said Dr Arthur Maka at the hospital.
MSF started a screening and treatment program in the Mboki area this year and have so far found in some settlements that up to eight percent of people are infected with the disease.
Total eradication will be difficult given the region's many refugees from Sudan, who move back and forth over the border.
"But the impact we can potentially have here could be huge," said a MSF worker.