ZAMFARA, Nigeria (Thomson Reuters Foundation) - When six-year old Mohammed Waziga arrived at a health centre in northwest Nigeria complaining of joint pains and drowsiness, he was given an injection and sent home without any concerns. However his suffering grew worse, and his family rushed him to a different facility in Zamfara state, where he was diagnosed with meningitis, marking yet another case in an outbreak which has killed more than 800 people so far this year in the north. "We are grateful to Allah that he got better," his grandmother Zainab said at the health centre, sitting next to Mohammed who was lying on a makeshift bed under a shea tree because there was no room for him in any of the wards. "He keeps asking me when we will go home, and I worry again that I will lose him," she told the Thomson Reuters Foundation. Thousands of meningitis cases have been reported by the health ministry in the northern states Zamfara, Kebbi, and Sokoto since November 2016, in Nigeria's worst outbreak of the disease since it killed more than 2,000 people in 2009. Meningitis is the inflammation of tissue surrounding the brain and spinal cord, which can be caused by viral or bacterial infections. It spreads mainly through kisses, sneezes, coughs and in close living quarters. Nigeria has launched a mass vaccination campaign and started conducting house-to-house searches to identify those afflicted with meningitis for treatment, as the state and aid agencies race to contain the surge in infections in recent months. [nL8N1HY6OS] "What is important now is that we provide an information vaccine to our people, on how the virus is contracted and warn against cross infection," said Yusuf Lawal, state coordinator for the Maternal, Newborn and Child Health (MNCH2) programme.