The Ministry of Health and Population (Ministère de la Santé et de la Population – MSP) of the Republic of the Congo, declared on 17 July 2023 a suspected triple outbreak of gastroenteritis, with typhoid fever, shigellosis, and cholera as probable causes.
Since the first case was reported on 28 June 2023, and as of 29 August 2023, a total of 2389 suspected cases have been reported, including 52 deaths (overall Case Fatality Rate (CFR) 2.2%).Laboratory analyses performed by the National Public Health Laboratory, identified 83 cases of Shigella, 22 of Salmonella Typhi (S. Typhi) and 21 cases of Vibrio cholerae with toxigenicity testing of the strain not performed.The city of Dolisie, the capital of Niari Department in the western part of the country is the epicentre of this outbreak. With WHO support, the MSP has activated a multisectoral coordination mechanism, strengthening surveillance, laboratory and clinical care capacities, and implementing decontamination and risk communication activities. An in-depth epidemiological investigation is also being led by the MSP. WHO assesses the risk posed by this triple outbreak as high at the national level, moderate at the regional level and low at the global level. Description of the situation On 14 July 2023, the Ministry of Health and Population of the Republic of the Congo reported 1384 cases whose dominant symptomatology was fever (39°C and 40°C), headaches, abdominal pain, diarrhoea, vomiting, and fatigue. On 17 July 2023, the MSP officially declared a suspected triple outbreak of gastroenteritis, with typhoid fever, shigellosis, and cholera as probable causes. The first case of the outbreak was reported on 28 June 2023. Since then, and as of 29 August 2023, a total of 2389 suspected cases have been reported, including 52 deaths (overall CFR 2.2%). Suspected typhoid fever cases accounted for 50.2% (n=1200) of all cases, followed by shigellosis (46.9%; n=1120) and cholera (2.9%; n=69). Eighty-eight (3.7%) of the suspected cases have undergone emergency surgery due to an intestinal perforation, a complication known to occur in untreated typhoid fever. The city of Dolisie – the capital of Niari Department with a population of more than 110 000 inhabitants – is the current epicentre of this outbreak, with 2178 suspected cases (91.2% of all cases) and 33 deaths (CFR 1.5%) reported for all three infectious diseases combined. Since the beginning of this outbreak, Dolisie has registered an overflow of health facilities with more than 600 suspected cases admitted during July-August. A reduction in the number of admitted patients has been observed since September. Five other departments in the Republic of Congo (Bouenza, Brazzaville, Kouilou, Pointe-Noire and Pool) have also reported suspected cases. Of the 2071 cases (86.7%) with information on age and sex, 51.6% (n=1068) were females, and the most affected age group was 11-20 years (n=674; 32.5%), followed by the 0-10 age group (n=506; 24.4%) and the 21-30 age group (n=403; 19.4%). The results of the antibiogram conducted on 78 samples of stool analysed, indicated a resistance and/or reduced susceptibility to carbapenems, third generation cephalosporins, and quinolones in several of the reported isolates of Shigella and Salmonella, while most of S. Typhi isolates are reported to be susceptible to ciprofloxacin (the number of the antibiogram results by pathogen and drug is unknown). Epidemiology of the diseases Cholera is an acute enteric infection caused by ingesting the bacteria Vibrio cholerae present in contaminated water or food. It is mainly linked to insufficient access to safe drinking water and inadequate sanitation. It is an extremely virulent disease that can cause severe acute watery diarrhoea resulting in high morbidity and mortality, and can spread rapidly, depending on the frequency of exposure, the exposed population and the setting. Cholera affects both children and adults and can be fatal if untreated. The incubation period is between 12 hours and five days after ingestion of contaminated food or water. Most people infected with V. cholerae do not develop any symptoms, although the bacteria are present in their faeces for 1-10 days after infection and are shed back into the environment, potentially infecting other people. The majority of people who develop symptoms have mild or moderate symptoms, while a minority develop acute watery diarrhoea and vomiting with severe dehydration. Cholera is an easily treatable disease. Most people can be treated successfully through prompt administration of Oral Rehydration Solution (ORS). After decades of progress against cholera, an upsurge has been recorded in several countries since 2021. From 1 January 2023 to 15 August 2023, at least 28 countries have reported cholera cases, compared with 16 countries in the same period of 2022. The WHO African Region is the most affected region with 16 countries reporting cholera cases since the beginning of 2023. In Congo, from 1997 to 2016, a total of six cholera outbreaks have been reported, with the last occurred in Mpouya (Plateaux Department), with 18 cases including three deaths (CFR 16.7%). Shigellosis is a gastrointestinal infection caused by one of four species of Shigella bacteria (Shigella sonnei, S. flexneri, S. boydii and S. dysenteriae). It is found in the intestinal tract of infected people and can be transmitted through the faecal-oral route by direct or indirect contact (e.g., through flies) with faeces from an infected person, fomites, consumption of contaminated food or water and person-to-person contact. Sustained sexual transmission has become an important component of Shigella species epidemiology. Humans are the only reservoir and can excrete bacteria in their stools for weeks after a dysenteric episode. Adequate antibiotic treatment can reduce the carriage status. Asymptomatic carriers can also contribute to the spread of the disease. Fluoroquinolones, cephalosporins, and azithromycin are recommended to treat more severe cases with underlying conditions or to limit transmission. Typhoid fever is a life-threatening infection caused by the bacterium Salmonella Typhi. It is usually spread through contaminated food or water. Once Salmonella Typhi bacteria are ingested, they multiply and spread into the bloodstream. Symptoms include prolonged fever, fatigue, headache, nausea, abdominal pain, and constipation or diarrhoea. Some patients may have a rash. Severe cases may lead to serious complications, such as intestinal perforation, or even death. Patients can be treated with antibiotics although increasing resistance to different types of antibiotics is making treatment more complicated. WHO has prequalified two typhoid conjugate vaccines since December 2017 and are being introduced into childhood immunization programs in typhoid-endemic countries.