Background: Ticks are important vectors of various pathogenic protozoa, bacteria and viruses that cause serious and life-threatening illnesses in humans and animals worldwide. Estimating tick-borne pathogen prevalence in tick populations is necessary to delineate how geographical differences, environmental variability and host factors influence pathogen prevalence and transmission. This study identified ticks and tick-borne pathogens in samples collected from June 2016 to December 2017 at seven sites within the Coastal, Sudan and Guinea savanna ecological zones of Ghana. Methods: A total of 2016 ticks were collected from domestic animals including cattle, goats and dogs. Ticks were morphologically identified and analysed for pathogens such as Crimean-Congo haemorrhagic fever virus (CCHFV), Alkhurma haemorrhagic fever virus (AHFV), Rickettsia spp. and Coxiella burnetii using polymerase chain reaction assays (PCR) and sequence analysis. Results: Seven species were identified, with Amblyomma variegatum (60%) most frequently found, followed by Rhipicephalus sanguineus sensu lato (21%), Rhipicephalus spp. (9%), Hyalomma truncatum (6%), Hyalomma rufipes (3%), Rhipicephalus evertsi (1%) and Rhipicephalus (Boophilus) sp. (0.1%). Out of 912 pools of ticks tested, Rickettsia spp. and Coxiella burnetii DNA was found in 45.6% and 16.7% of pools, respectively, whereas no CCHFV or AHFV RNA were detected. Co-infection of bacterial DNA was identified in 9.6% of tick pools, with no statistical difference among the ecozones studied. Conclusions: Based on these data, humans and animals in these ecological zones are likely at the highest risk of exposure to rickettsiosis, since ticks infected with Rickettsia spp. displayed the highest rates of infection and co-infection with C. burnetii, compared to other tick-borne pathogens in Ghana. Graphical
Understanding the underlying epidemiology that shapes Neisseria gonorrhoeae (GC), and Chlamydia trachomatis (CT) infections can contribute to data driven policies directed towards curbing the proliferation of these pathogens in Ghana. Information on the symptoms and risk factors for STIs will help to identify high-risk individuals which will in turn inform STI syndromic management and tailor the use of public health resources. Participants were from 4 military clinics and 1 civilian STI clinic in Ghana and eligible if they had symptoms suggestive of STI. First void urine samples were collected and tested with Nucleic Acid Amplification Test (NAAT). A structured questionnaire was administered to all participants. Multivariate logistic regression identified factors associated with infection, separately for NG and for CT and for men and women. A total of 950 patients, 58% of whom were females were enrolled, 28% had gonorrhea and 11% had chlamydia with more males testing positive than females. Reported symptoms that were more common among patients who tested positive for gonorrhea were painful urination and urethral discharge (all P values < 0.05). Additionally, multiple sexual partners and alcohol use were statistically associated with higher rates of gonorrhea in males while only the frequency of condom use was associated with gonorrhea for females. None of the symptoms or risk factors except marital status was associated with testing positive for chlamydia. Identifying these symptoms and risk factors help inform health care delivery systems for STIs in Ghana. Furthermore, men and women presenting with these symptoms and risk factors are a prime target for public health education campaigns, aimed at curbing the spread of gonorrhea and chlamydia infections.
1 November 2023 in The American Journal of Tropical Medicine and Hygiene
: Malaria remains the leading cause of acute febrile illness (AFI) in Africa despite successful control measures and programs. Acute febrile illnesses can be misdiagnosed as malaria as a result of the overlapping spectrum of nonspecific symptoms or may not be pursued because of limited diagnostic capabilities. This study investigated potential etiologies of AFIs in Ghana and determined the relationship between coinfection between malaria and Q fever, leptospirosis, and culturable bacteria in febrile patients. Participants were enrolled between July 2015 and December 2019 from four Ghanaian military treatment facilities. Of the 399 febrile participants, 222 (55.6%) males and 177 (44.6%) females were enrolled. Malaria was diagnosed in 275 (68.9%) participants. Malaria coinfection occurred with leptospirosis, Q fever, and blood-cultured bacteria in 11/206 (5.3%), 24/206 (11.7%), and 6/164 (3.7%) participants, respectively. Among the 124 malaria-negative samples, the positivity rates were 4.1% (3/74), 8.1% (6/74), and 3.6% (2/56) for leptospirosis, Q fever, and bacterial pathogens isolated from blood culture, respectively. The majority of documented clinical signs and symptoms were not significantly associated with specific diseases. Approximately 10% of malaria-positive participants also had evidence suggesting the presence of a bacterial coinfection. Therefore, even in the case of a positive malaria test, other pathogens contributing to febrile illness should be considered. Understanding the frequency of malaria coinfection and other etiological agents responsible for AFIs will improve diagnosis and treatment and better inform public health knowledge gaps in Ghana.
Staphylococcus aureus (S. aureus) is a common cause of surgical site infections (SSIs) globally. Data on the occurrence of methicillin-susceptible S. aureus (MSSA) as well as methicillin-resistant S. aureus (MRSA) among patients with surgical site infections (SSIs) in sub-Saharan African are scarce. We characterized S. aureus from SSIs in Ghana using molecular methods and antimicrobial susceptibility testing (AST). Wound swabs or aspirate samples were collected from subjects with SSIs. S. aureus was identified by matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF-MS); AST was performed by Kirby-Bauer disk diffusion, and results were interpreted according to the Clinical and Laboratory Standards Institute (CLSI) guideline. Detection of spa, mecA, and pvl genes was performed by polymerase chain reaction (PCR). Whole-genome sequencing (WGS) was done using the Illumina MiSeq platform. Samples were collected from 112 subjects, with 13 S. aureus isolates recovered. Of these, 92% were sensitive to co-trimoxazole, 77% to clindamycin, and 54% to erythromycin. Multi-drug resistance was detected in 5 (38%) isolates. The four mecA gene-positive MRSA isolates detected belonged to ST152 (n = 3) and ST5 (n = 1). In total, 62% of the isolates were positive for the Panton-Valentine leukocidin (pvl) toxin gene. This study reports, for the first time, a pvl-positive ST152-t355 MRSA clone from SSIs in Ghana. The occurrence of multi-drug-resistant S. aureus epidemic clones suggests that continuous surveillance is required to monitor the spread and resistance trends of S. aureus in hospital settings in the country.
30 January 2024 in The American Journal of Tropical Medicine and Hygiene
The threats from vector-borne pathogens transmitted by ticks place people (including deployed troops) at increased risk for infection, frequently contributing to undifferentiated febrile illness syndromes. Wild and domesticated animals are critical to the transmission cycle of many tick-borne diseases. Livestock can be infected by ticks, and serve as hosts to tick-borne diseases such as rickettsiosis. Thus, it is necessary to identify the tick species and determine their potential to transmit pathogens. A total of 1,493 adult ticks from three genera—Amblyomma, Hyalomma, and Rhipicephalus—were identified using available morphological keys and were pooled (n = 541) by sex and species. Rickettsia species were detected in 308 of 541 (56.9%) pools by genus-specific quantitative polymerase chain reaction assay (Rick17b). Furthermore, sequencing of the outer membrane protein A and B genes (ompA and ompB) of random samples of Rickettsia-positive samples led to the identification of Rickettsia aeschlimannii and Rickettsia africae with most R. africae DNA (80.2%) detected in pools of Amblyomma variegatum. We report the first molecular detection and identification of the rickettsial pathogens R. africae and R. aeschlimannii in ticks from Ghana. Our findings suggest there is a need to use control measures to prevent infections from occurring among human populations in endemic areas in Ghana. This study underscores the importance of determining which vector-borne pathogens are in circulation in Ghana. Further clinical and prevalence studies are needed to understand more comprehensively the clinical impact of these rickettsial pathogens contributing to human disease and morbidity in Ghana.
5 May 2026 in The American Journal of Tropical Medicine and Hygiene
: Zoonotic diseases account for more than 60% of emerging infectious diseases, and they are the leading cause of pandemics. As humans and livestock become increasingly transient and the environment and climate change, disease vectors expand into previously untouched geographical regions, spreading pathogens. In this study, we assessed the seroprevalence of arthropod-borne and hemorrhagic fever viruses of similar clinical presentation and endemicity in high-risk populations in Ghana (animal handlers). Using a microneutralization assay, we compared total IgG prevalence with live virus neutralizing response. In total, 300 blood samples were collected from consenting healthy adults at five military and three civilian sites across Ghana. The observed seroprevalence rates for Rift Valley fever virus (RVFV), Crimean–Congo hemorrhagic fever virus (CCHFV), Ebola virus, Lassa virus, and Marburg virus were 14.7%, 7.0%, 2.3%, 1%, and 0%, respectively. Microneutralization data further verified virus-specific neutralization positives of the total IgG positives. Among animal handlers who had recently skinned livestock, 19 (25.3%) were exposed to RVFV, and 20 (28.6%) of those in the coastal savannah ecological zone were also more likely to be exposed to RVFV compared with those in the other ecological zones ( P = 0.002). Animal handlers younger than 25 years old had a higher exposure rate to CCHFV than those older than 25 years old ( P <0.001). These data help us better understand the risk of exposure to zoonotic and vector-borne diseases in the region. Moreover, this study establishes methods for assessing seropositivity in a multiplexed format for higher-throughput sample analysis.