An outbreak of dengue fever in the northeastern Kenyan town of Mandera, northeastern Kenya, close to the Somalia and Ethiopia borders, has affected more than 1,000 people, with four unconfirmed deaths, according to the Ministry of Public Health and Sanitation and the World Health Organization (WHO). According to WHO, \"Dengue is a mosquito-borne infection that causes a severe flu-like illness, and sometimes a potentially lethal complication called dengue haemorrhagic fever.\" The \"attack rate is very high but mortality is very low\", the ministry said in a statement. A permanent river, Dawa, passes through Mandera. Health officials said residents had been complaining of mosquito bites during the day with the bites swelling. \"Using bed nets was impractical as the vector was biting during the day,\" the ministry said. \"The Public Health office has also noted the resistance developed by the vector to insecticides of different varieties (Icon and Deltamethrin mainly).\" Health authorities have alerted all neighbouring districts and public awareness campaigns are ongoing, advising residents to seek early medical attention. An outbreak of dengue fever in Mandera, northeastern Kenya, is spreading fast, with at least 5,000 people infected within weeks, due to limited health facilities, a shortage of medical personnel and poor sanitation, officials told IRIN, the humanitarian news and analysis, a service of the UN Office for the Coordination of Humanitarian Affairs . With only one public hospital and a few private clinics, medical officials in the town - which borders Ethiopia and Somalia - said the facilities were congested with dengue fever patients and they were unable to cope. \"Mandera District Hospital is congested, many patients and panicked residents are streaming into the facility, it\'\'s the only public hospital, all wards are occupied above capacity,\" Mohamed Sheikh, the provincial public health and medical officer, told IRIN. \"At the moment, more than 5,000 cases have been recorded, and a large number of other cases - about half of those attending Mandera government hospital - have been treated in the few private clinics.\" The UN World Health Organization (WHO) describes dengue as \"a mosquito-borne infection that causes a severe flu-like illness, and sometimes a potentially lethal complication called dengue haemorrhagic fever\". The WHO estimates some 50 million people are infected with dengue across the world every year. A statement by the Ministry of Public Health and Sanitation on 26 September said four deaths from the disease had been confirmed but, according to Mandera residents, at least 10 people have died since early September when the outbreak started. Sheikh said more deaths resulting from the viral infection could have occurred in homes or at private clinics. \"Symptoms of dengue fever case are easily mistaken for malaria and anti-malaria drugs were prescribed to many suspected patients for two weeks, then we got concerned when we received more cases, conducted tests last week and confirmed almost all our patients required new treatment for this viral infection,\" Sheikh said. In the absence of a specific treatment for dengue fever, Sheikh said, health facilities were providing supportive treatment to the infected: Paracetamol for those presenting with fever, fluids for those dehydrated and antibiotics for those with infections. He added that the fever often subsides after seven days. Sheikh said the disease was believed to have spread from neighbouring Somalia where several deaths and cases have been reported this year.