Minimal Rickettsial Infection Rates and Distribution of Ticks in Uganda: An Assessment of the Seasonal Effects and Relevance to Tick-Borne Disease Risk in East Africa

Corrigan, James; Marion, Brianna; English, James J.; Eneku, Wilfred; Weng, Ju Lin; Rugg, Molly; Dotrang, Thoai; Dunford, James C.; Byaruhanga, Anatol M; Byarugaba, Denis K.; Ramalho-Ortigão, Marcelo; Wanja, Elizabeth

doi:10.1093/jme/tjac166

Cited by 8 publications

(9 citation statements)

References 22 publications

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“…This is the first report of SFGR among Ugandan patients presenting at health facilities with acute undifferentiated fever. Previously, SFGR has been isolated in ticks in Uganda but not in AFI patients [ 16 , 49 ]. Our findings confirm that arthropod vector-borne infections are diseases of major clinical and public health importance in Uganda.…”

Section: Discussionmentioning

confidence: 99%

Investigating the etiology of acute febrile illness: a prospective clinic-based study in Uganda

Kigozi

Kharod²,

Bukenya

et al. 2023

BMC Infect Dis

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Background Historically, malaria has been the predominant cause of acute febrile illness (AFI) in sub-Saharan Africa. However, during the last two decades, malaria incidence has declined due to concerted public health control efforts, including the widespread use of rapid diagnostic tests leading to increased recognition of non-malarial AFI etiologies. Our understanding of non-malarial AFI is limited due to lack of laboratory diagnostic capacity. We aimed to determine the etiology of AFI in three distinct regions of Uganda. Methods A prospective clinic-based study that enrolled participants from April 2011 to January 2013 using standard diagnostic tests. Participant recruitment was from St. Paul’s Health Centre (HC) IV, Ndejje HC IV, and Adumi HC IV in the western, central and northern regions, which differ by climate, environment, and population density. A Pearson's chi-square test was used to evaluate categorical variables, while a two-sample t-test and Krukalis-Wallis test were used for continuous variables. Results Of the 1281 participants, 450 (35.1%), 382 (29.8%), and 449 (35.1%) were recruited from the western, central, and northern regions, respectively. The median age (range) was 18 (2–93) years; 717 (56%) of the participants were female. At least one AFI pathogen was identified in 1054 (82.3%) participants; one or more non-malarial AFI pathogens were identified in 894 (69.8%) participants. The non-malarial AFI pathogens identified were chikungunya virus, 716 (55.9%); Spotted Fever Group rickettsia (SFGR), 336 (26.2%) and Typhus Group rickettsia (TGR), 97 (7.6%); typhoid fever (TF), 74 (5.8%); West Nile virus, 7 (0.5%); dengue virus, 10 (0.8%) and leptospirosis, 2 (0.2%) cases. No cases of brucellosis were identified. Malaria was diagnosed either concurrently or alone in 404 (31.5%) and 160 (12.5%) participants, respectively. In 227 (17.7%) participants, no cause of infection was identified. There were statistically significant differences in the occurrence and distribution of TF, TGR and SFGR, with TF and TGR observed more frequently in the western region (p = 0.001; p < 0.001) while SFGR in the northern region (p < 0.001). Conclusion Malaria, arboviral infections, and rickettsioses are major causes of AFI in Uganda. Development of a Multiplexed Point-of-Care test would help identify the etiology of non-malarial AFI in regions with high AFI rates.

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Section: Discussionmentioning

confidence: 99%

Investigating the etiology of acute febrile illness: a prospective clinic-based study in Uganda

Kigozi

Kharod²,

Bukenya

et al. 2023

BMC Infect Dis

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“…The virus has been described in Europe (it is also known as Alongshan virus in Russia and Finland) (20, 21), and more recently in Kenya in several tick species including R. appendiculatus, R. evertsi evertsi, H. truncatum collected from cattle and sheep, and A.sparsum, A.nuttalli and Amblyoma nymphs collected from tortoises (22). In Uganda, JMTV has also been isolated from non-human primates (colobus monkeys), highlighting the potential risk to primates (23).…”

Section: Discussionmentioning

confidence: 99%

“…R. appendiculatus ticks, the most prevalent species, are known to be widespread in Uganda and lack seasonal variation in abundance (17)(18)(19)(20). They are also well-described vectors for zoonotic diseases, as they feed on a wide range of animals as well as humans (21,22), including CCHFV (23,24), Nairobi Sheep Disease Virus (NSDV) (25) and Kadam virus (26,27), all of which are prevalent in Uganda.…”

Section: Discussionmentioning

confidence: 99%

Ticks; a reservoir for virus emergence at the human-livestock interface in Uganda

Atim

Ashraf

Niebel

et al. 2023

Preprint

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Background: Uganda is one of the most biodiverse regions on the planet and a hotspot for virus emergence. In particular, the warm-humid lowlands favour tick population growth with the associated risk of tick-borne disease. The prevalent tick species Rhipicephalus appendiculatus, R. evertsi evertsi and Amblyomma variegatum harbour a diverse range of viruses, from harmless to highly pathogenic. Notably, the orthonairoviruses cause human outbreaks of Crimean-Congo haemorrhagic fever (CCHF) regularly within the cattle corridor of Uganda, a region spanning from the south-west to the north-east of the country. Methods: In the ArboViral Infection (AVI) study, the first to explore the virome of ticks in Uganda using next generation sequencing (NGS), we collected ticks from three geographically diverse areas and subjected these to target-enrichment (TE) NGS. Viral genomes were detected by de novo assembly, mapping and BLASTn. Results: We analyzed a total of 2,754 ticks collected from 31 livestock farms in the districts of Arua, Nakaseke and Lyantonde. These were combined into 219 pools by site of collection and tick species, including R. appendiculatus, R. evertsi evertsi, A. variegatum and Hyalomma rufipes. We detected partial or near-complete viral genomes in 163 tick pools; 110 (67%) of which were from Arua, 39 (24%) from Nakaseke and 12 (7%) from Lyantonde districts. 2 pools (2%) were from Arua/Lyantonde. These included 22 species of virus, representing 15 genera and 9 families, including the Nairoviridae, Retroviridae, Orthomyxoviridae, Chuviridae, Rhabdoviridae, Phenuiviridae, Parvoviridae, Poxviridae and Flaviviridae. There were 8 viral species known to be pathogens of humans or animals and 5 highly divergent genomes detected, representing novel virus species. A high abundance of orthonairoviruses was notable, including CCHFV, Dugbe virus and a novel Orthonairovirus species that we have named Macira virus.

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“…Diverse species of ticks have been recovered from both animals and the environment in two regions of the country, the northeast and southwest, often carrying medically relevant human and animal pathogens (19)(20). We recently reported the abundance and distribution of seven tick species of the Rhipicephalus, Haemaphysalis, and Amblyomma genera in the Ugandan cattle corridor with rickettsial pathogens detected (21). Tick-borne Rickettsia spp.…”

Section: Introductionmentioning

confidence: 99%

“…While there is evidence of widespread Rickettsia spp. present throughout sub-Saharan Africa, there is limited data about the type and frequency in Ugandan ticks (21). Therefore, it is essential to characterise ticks and their associated Rickettsia spp.…”

Section: Introductionmentioning

confidence: 99%

Wide distribution of Mediterranean and African Spotted fever agents and the first identification of Israeli Spotted Fever agent in ticks in Uganda

Eneku

Erima

Byaruhanga

et al. 2023

Preprint

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Rickettsia microorganisms are causative agents of several neglected emerging infectious diseases transmitted to humans by ticks among other arthropod vectors. In this study, ticks were collected from four geographical regions of Uganda, pooled in sizes of 1-179 ticks based on location, tick species, life stage, host, and time of collection, and were tested by real time PCR for Rickettsia species harboured. The tick pools were tested with primers targeting gltA, 17kDa and ompA genes, followed by Sanger sequencing of 17kDa and ompA genes. Of the 471 tick pools tested, 116 (24.6%) were positive for Rickettsia spp. by the gltA primers. The prevalence of Rickettsia varied by district with Gulu recording the highest (30.1%) followed by Luwero (28.1%) and Kasese had the lowest (14%). Tick pools with highest positivity rates were from livestock (cattle, goats, sheep, and pigs), 26.9%, followed by vegetation 23.1% and pets (dogs and cats) 19.7%. Of 116 gltA-positive tick pools, 86 pools were positive using 17kDa primers of which 48 purified PCR products were successfully sequenced. The predominant Rickettsia spp. identified was R. africae (n=15) in four tick species, followed by R. conorii (n=5) in three tick species (Haemaphysalis elliptica, Rhipicephalus appendiculatus, and Rh. decoloratus). Rickettsia conorii subsp. israelensis was detected in one tick pool. These findings indicate that multiple Rickettsia spp. capable of causing human illness are circulating in the four diverse geographical regions of Uganda including new strains previously known to occur in the Mediterranean region. Physicians should be informed about Rickettsia spp. infections as potential causes for acute febrile illnesses in these regions. Continued and expanded surveillance is essential to further identify and locate potential hotspots with Rickettsia spp. of concern.

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Minimal Rickettsial Infection Rates and Distribution of Ticks in Uganda: An Assessment of the Seasonal Effects and Relevance to Tick-Borne Disease Risk in East Africa

Cited by 8 publications

References 22 publications

Investigating the etiology of acute febrile illness: a prospective clinic-based study in Uganda

Investigating the etiology of acute febrile illness: a prospective clinic-based study in Uganda

Ticks; a reservoir for virus emergence at the human-livestock interface in Uganda

Wide distribution of Mediterranean and African Spotted fever agents and the first identification of Israeli Spotted Fever agent in ticks in Uganda

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