Investigation of an imported case of Dengue fever, Uganda, November 2018

Affiliations: 1Uganda Public Health Fellowship Program, Kampala, Uganda,  2Epidemiology Surveillance Division, Kampala, Uganda, 3Infectious Disease Institute, Kampala, Uganda

Summary

Dengue fever is under-recognized disease despite being of public health importance and incidence has increased reaching new territories. Uganda is at risk of dengue fever though has not experienced a documented locally triggered outbreak hence the importance of critical control of any foreign infection from contaminating the population. On 27 November 2018, ministry of Health Uganda received a confirmation of Dengue fever by the Uganda Virus Research Institute (UVRI) in a sample from one of the hospitals in Kampala District. The case-patient was from India. We investigated to locate his whereabouts and travel history within the country as well as monitor his viremia. We used the hosts of the case-patient to locate his whereabouts. He was an Islam missionary from Asam State – India who had started his journey to Uganda on 2 October 2018 and arrived in Uganda on 31 October 2018. He had moved from Kajjansi to Arua then Yumbe. He was intercepted in Yumbe travelling in a group of 9. We held interviews with the case-patient and his team to identify potentially ex-posed contacts. We took blood samples from the case-patient and his team. The entire group were negative for Dengue. The suspect had been in Uganda for 27 days before investigations started. This highlighted the gap in detection and how porous our borders are to such infectious diseases. We recommended the Ministry of Health to improve detection of Dengue fever at the border and reduction of turnaround time of laboratory results.

Introduction

Dengue fever is an acute febrile disease caused by the Dengue Virus (DENV). The virus is from genus Flavivirus and has four serotypes (1-4). Primarily Aedes egypti mosquitoes transmit DENV though other Aedes species such as albopictus, adricanus and luteodephalus [5]. The incubation period in humans is 4-7 days, and it takes an infected mosquito 8-12 days to transmit the virus to humans. The disease manifests with high fever, headache, stomach-ache, rash, myalgia, and arthralgia though the disease can be severe with haemorrhaging and shock, usually leading to death [2].
Dengue is under recognized despite being of a disease of public health importance and incidence has increased reaching new territories. In Africa, epidemics have increased drastically since 1980 and have mostly been reported from Eastern Africa [2]. Fortunately, Uganda has only experienced imported dengue cases with the latest having been UPDF soldiers that had returned from a peace mission in Somalia [3].
Uganda is at risk of dengue fever[4]. The primary driving factors for outbreaks such as rapid and unplanned urbanization, lack of vector control and surveillance, poor public health pro-grams and porous borders are in maximum existence [2, 5, 6]. At the moment, Uganda has not experienced a documented locally triggered outbreak. To maintain this, any dengue fever case detected by the system should be quickly investigated to mitigate further infections.
On 27 November 2018, ministry of Health Uganda received a confirmation of Dengue fever by the Uganda Virus Research Institute (UVRI) (by PCR and other serological tests) in a sample from one of the hospitals in Kampala District. The patient was said to have travelled from India. Having the virus active in blood based on the PCR result, the case-patient was still infectious at the time of arrival in Uganda[1]. We investigated to locate the case and find out more information regarding his illness and movements within the country.

Methods

We used Ugandan coordinators of the mission to locate the case-patient. We interviewed the case-patient and his team to track movements within the country. We took samples from the case-patient and team he moved with to test for acute dengue fever infection.

Description of case-patient

The case-patient was a 50-year-old male from India that arrived in Uganda on 31 October 2018. On 2 November 2018, the case was taken to one of the Muslim hospitals in Kampala after having headache. He was asymptomatic with medical records complied from India that included an RDT+ result for Dengue fever. He was in Uganda as an Islam missionary and part of a bigger team of missionaries that were moving around the Uganda. The missionaries usually move around different mosques preaching Islam and reportedly sleep and reside within the mosques. The case-patient was confirmed to have Dengue virus on 19 December 2018 approximately 17 days after sample was taken.
The movements made by the case-patient. The case arrived on 31 October 2018; he was first hosted at Kajjansi mosque. He travelled to Arua and Yumbe District. The movement of the case from India and within Uganda are summarized below:

2 October 2018: The team started the journey from Morigoan District, Asam State India to Delhi city (approx. 2000km apart). They stayed in Delhi till 27 October 2018.
27 October 2018: The team travelled to Mumbai where they stayed at Mumbai Town Mosque for 3 days till 29th of October
29 October 2018: Case-patient developed first symptoms (ill-feeling)
30 October 2018: Case-patient to hospital in Mumbai and test-ed RDT+ve for Dengue however left for Uganda the same day for the mission.
31 October 2018: The team arrived at Entebbe and were hosted in Bweya-Kajjansi near the snake park for 3 days.
2 Nov 2018: The case-patient was taken to Kibuli Muslim Hos-pital feeling sick and given drugs; also a blood sample was drawn for confirmatory test at UVRI.
3 Nov 2018: They travelled to Arua and were hosted at Mukhtar mosque for 4 days
7 Nov 2018: They travelled to Yumbe and were hosted at Yumbe Town Council Mosque for 5 days
12 Nov 2018: They moved to Lomunga mosque, Yumbe and were hosted till 16 Nov 2018
17 Nov 2018: They moved to Barakara mosque where they stayed till 21 Nov 2018
22 Nov 2018: They moved to Midigo mosque and hosted for 9 days
27 Nov – 7 Dec 2019: They were hosted at Kulu Centre mosque where they were sampled for dengue

Laboratory findings

All the group members tested negative for dengue fever by PCR.

Discussion

The missionary work that the case-patient was to do in Uganda was the cause of the concern in this investigation. He was to move around different mosques in the country preaching and residing for a few nights at each. With this work, the missionary sleeps in the mosques premises with the rest of his team in conditions that were unknown. At the time he was sampled, he still had a high viremia. We suspected he could have exposed some of his team members. The duration of the case-patient in Uganda before investigations was ample time to expose all the team members. We fortunately found none of the group members infected.
Presence of aedes mosquitoes in Uganda makes transmission of Dengue fever highly possible. Despite having no indigenous outbreak confirmed, Uganda is at high risk and her neighbors have already had dengue fever [4]. It is therefore important to limit transmission from any imported cases.

Conclusions and recommendations

Dengue fever was imported in Uganda and all the possibly ex-posed people did not contract the disease. There was delayed laboratory confirmation of the case. We therefore recommend the UVRI to ensure faster laboratory confirmation of suspected dengue fever cases. Uganda does not have dengue fever RDT tests supplied by Ministry of Health especially at the airports and border towns therefore potential of missing cases as they enter the country. We recommend these tests be availed at all cross-border points in the country. Dengue fever and importance of surveillance should be re-echoed to health workers to comprehend its public health importance.

References

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