Crimean-Congo Haemorrhagic Fever Outbreak in Kakumiro and Mubende Districts, Central Uganda, May – August 2018

Summary

Crimean–Congo haemorrhagic fever (CCHF) is a viral haemorrhagic fever typically spread by tick bites or contact with body fluids of infected livestock or animals. Onset of symptoms is less than two weeks following exposure and may include fever, muscle pains, headache, vomiting, diarrhoea, and skin bleeding. Those affected are often farmers or people who work in slaughterhouses.

Diagnosis is by detecting antibodies, the virus’s RNA, or the virus itself. Following a death report of a suspected Viral Haemorrhagic Fever (VHF) case person at Mubende hospital on the 23rd of May 2018, the Uganda Virus Research Institute (UVRI) confirmed the case positive for CCHF virus by both RT-PCR and immunoglobulin (IgM serology).

We formulated a Rapid Response Team (RRT) to conduct a quick outbreak investigation, carry out a rapid risk assessment and initiate immediate control measures. We defined a confirmed case as a positive CCHF test by both RT-PCR and immunoglobulin (IgM) serology in a resident of Kakumiro and Mubende District since the 1st of May 2018. We reviewed patient records at Kakumiro health centre IV, Nkooko health centre III and Mubende regional referral Hospital.

We designed a standardised case and contact investigation questionnaire, and trained a team of Village Health Teams (VHTs) to perform active case finding and contact tracing. We also collected human, livestock blood samples and ticks for CCHF virus testing. One confirmed case (AR = .31/100,000) with a Case Fatality Rate (CFR) of 100% was reported from Lubumbo village in Nkooko subcounty, Kakumiro District.

We identified 32 contacts, 11/32 (34%) were relatives, 9/32(28%) were Health workers and 12/32 (38%) were community members. We also calculated Weighted Risk scores (WRS) and found 6/32 (19%) relatives with a WRS above 9 points.

However, none of them developed symptoms. Although the case patient owned no livestock, IgM seropositivity of 23% was found in the neighbourhood livestock but insignificant in ticks. The cause of this outbreak was probably exposure to CCHF virus-infected ticks and livestock meat. We recommended spraying of livestock with acaricides and disinfection of infected livestock owners’ homes.

Background

Crimean-Congo haemorrhagic fever is a viral haemorrhagic fever transmitted by ticks and caused by the Crimean-Congo Haemorrhagic Fever Virus (CCHFV) of the genus Nairovirus of the Bunyaviridae Family. It is the most widespread tick-borne virus in the world and is responsible for severe outbreaks in humans. Numerous wild and domestic animals, such as cattle, goats and are critical determinants for the establishment and maintenance of CCHF endemicity (3).

Transmission also occurs by close contact with bodily fluids of infected persons or animals. Cases commonly occur in agricultural workers, slaughterhouse workers and veterinarians. The incubation period is usually one to three days following a tick bite and five to six days, with a maximum of 13 days following contact with infected blood or tissues (4).

Symptoms are sudden, with fever, muscle ache, dizziness, neck pain and stiffness, backache, headache, sore eyes and photophobia (sensitivity to light). Nausea, vomiting, diarrhoea, abdominal pain and sore throat may occur, followed by sharp mood swings and confusion and later bleeding from body orifices(5). Mortality rate is between 10% and 40% in the second week of illness (4). The main approach to care in supportive and control measures include raising awareness of the risk factors, monitoring of contacts, active search of infective animals, vectors and use of acaricides.

There is currently no safe and effective vaccine widely available for human use(6). On 23rd May 2018, Kakumiro District health office received a report of death of a suspected Viral Haemorrhagic Fever case person at Mubende hospital. On the 22nd May 2018, a 35-year-old male, a resident of Lubumbo village in Nkooko Sub-county reported at Kakumiro HC IV with a history of sudden onset of high fever, severe headache, body pain and vomiting of blood. He visited two other private clinics 3 days earlier and had treatment without improvement.

A few hours later, Mubende Regional Referral Hospital admitted him in isolation, took a blood sample for CCHF testing and sent it to UVRI for CCHF testing. The medical team treated him with intravenous fluids and antipyretics but he died a few hours later on the night of 23rd May 2018. A day later, relatives took his body from hospital and buried him on the 24th of May 2018. A day later, the 25th May 2018, UVRI reported positive CCHF -PCR results of the dead patient to the Hoima Epidemiology and Surveillance (EPI/IDSR) regional office. A District rapid response team (RRT) was organised quickly conducted an outbreak investigation and initiate immediate control measures.

Methods

A confirmed case was any person that tested positive for CCHF by RT-PCR or immunoglobulin (IgM) serology from the districts of Mubende and Kakumiro since the 1st of May 2018. We defined a probable case as; sudden onset of fever >38oC (100.4oF) with any one of the following symptoms; loss of appetite, general body weakness, headache, vomiting, abdominal pain, diarrhoea, myalgia and/or joint pains and sudden-onset of unexplained bleeding or sudden death in a resident of Kakumiro and Mubende Districts since the 1st of May 2018.

We defined a contact as any person exposed to a confirmed case-patient in any of the following ways. Touching blood or other body fluids of the patient; touching patient’s clothes or linen; sleeping in the same household; direct physical contact with patient during the illness; direct physical contact with the corpse during burial preparation or funeral; or breastfed by a confirmed case-patient.

We reviewed medical records at facilities in the districts for active case search. We developed a contact investigation questionnaire and follow up tool for descriptive epidemiology. Weighted risk scores (WRS) are grades of exposure to disease that are used in VHF outbreaks to gauge the magnitude and risk of exposure.

Results

Case Description: A 35-year-old male peasant farmer from Lubumbo village in Rubumbo Parish of Nkooko Sub-county in Kakumiro District. On 19th May 2018, he reported to a private clinic in Rutooma village with a 3-day history of vomiting blood, a high-grade fever of 39 degrees Celcius, severe
headache and jaundice.

Two days later, on the 22 of May 2018, he presented to Kakumiro Health Center in severe pain, delirium, jaundice, anaemia and bleeding from the mouth. At about 10:30 pm on the same day, Mubende RRH received him in semi-conscious state with mouth and nose bleeding. He was isolated and managed on intravenous fluids. He died later in the night at about 1:00am, on the 23rd of May 2018.

An unsafe burial was performed on 24th of May 2018. On the 25th of May 2018, UVRI Entebbe confirmed his test results as positive for CCHFV by RT-PCR. His home was disinfected and thirty-two (32) contacts were line listed though none developed symptoms. All case patient relatives had WRS above 9 points but were negative for CCHFV. 25/42 contacts were Male, 11/32 were relatives and 9/32 were health workers.

The RRT team assigned WRS as follows; 1 for attending a funeral of the deceased; 2 for having slept in case-patients’ homes;3 for having touched or washed their clothes or utensils; 3 for having had direct contacts with their bodies; 4 for touching confirmed case-patient’s body or bodily fluids (such as blood, saliva, excreta) with PPE and 5 for touching their bodily fluids without PPE. We grouped them as WRS of 0-2, 3 -5, 6-8 and 9-10 points. We also took blood samples and ticks from 59 animals including 22 cows, 32 goats and 7 sheep in Lubumbo village for CCHF serology testing.

Place distribution:
22/32 (69%) contacts were from Lumumbo village in Nkooko Sub-county for Kakumiro District. 4/32 (13) were health workers from Kakumiro town council and 4/22 (13%) were health workers from Mubende RRH.

Environmental and Veterinary Investigations
The case patient had a history of contact with raw goat meat about 2 weeks prior to onset of symptoms. He owned no livestock but there was livestock like cattle, goats and sheep in the village which had 23% CCHF IgM seropositivity but insignificant for tick tests.

Discussion and Conclusion

There is unrestricted movement of both animals and persons across district boundaries. This movement probably propagated transmission of the virus into Kakumiro District. Since the neighbouring districts of Kyankwanzi and Kiboga had reported CCHF outbreak in January 2018(7), it is not surprising that Kakumiro District reported CCHF in May 2018.

The case patient was a peasant farmer and did not own any livestock. However, the community livestock grazes at free lance across different fields in his neighbourhood. He probably got exposed to tick from infected livestock in the neighbourhood (8). The district reported no other case patient during this outbreak. None of the relatives, health workers of community members who got in contact with him got infected.

This may be because of the mass media campaigns and community health education done by the nearby districts during the previous CCHF outbreaks reported in January 2018. The community members were quick to suspect VHF and minimise body contact with the patient. The medical teams were quick to suspect VHF too and used personal protective equipment (PPE) and disinfectants to minimise their exposure. The district had additional mass media sensitisations on avoiding handling ticks with bare hands and use of protective gear such as gloves, boots and clothes to minimize exposure to livestock.
The RRT also disinfected the deceased’s home. However, farmers have not sprayed their livestock with acaricides and the outbreak is likely reoccur. The outbreak of CCHFV in Kakumiro District was possibly caused by exposure to infected livestock. We recommend continued community health education on prevention of CCHF exposures, signs and symptoms, safe burial, spraying of livestock and seeking immediate medical care.

References

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1. Transmission | Crimean-Congo Haemorrhagic Fever (CCHF) | CDC [Internet]. [cited 2018 Jun 8]. Available from: https://www.cdc.gov/vhf/crimean-congo/transmission/ index.html
   

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2. Al-Abri SS, Abaidani IA, Fazlalipour M, Mostafavi E, Leblebicioglu H, Pshenichnaya N, et al. Current status of Crimean -Congo haemorrhagic fever in the World Health Organization Eastern Mediterranean Region: issues, challenges, and future directions. International Journal of Infectious Diseases. 2017 May 1; 58:82–9.
   

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3. Global distribution of Crimean-Congo haemorrhagic fever | Transactions of The Royal Society of Tropical Medicine and Hygiene | Oxford Academic [Internet]. [cited 2018 Jun 8]. Available from: https://academic.oup.com/trstmh/ article/109/8/503/1910424
   

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4. Crimean-Congo haemorrhagic fever [Internet]. World Health Organization. [cited 2018 Jun 8]. Available from: http://www.who.int/news-room/fact-sheets/detail/crimean-congo haemorrhagic-fever