Q fever, spotted fever group, and typhus group rickettsioses among hospitalized febrile patients in northern Tanzania

The case of Mediterranean spotted fever of the traveler returned from Zambia

We report the case of a traveler who returned from Zambia and was diagnosed with Mediterranean spotted fever (MSF), an infectious disease caused by Rickettsia conorii conorii. The patient presented to Sapporo City General Hospital with symptoms of fever, malaise, headache, and rash. The pathogen was identified by Polymerase Chain Reaction assays and subsequent analyses. The patient improved with 10-day treatment of oral doxycycline. Although some cases of MSF have been reported in sub-Saharan Africa, none have been reported in Zambia. Rhipicephalus sanguineus sensu lato, the vector of the Rickettsia conorii conorii, has been found in various areas of Zambia. Our case report highlights the potential threat of Mediterranean spotted fever in urban areas of Zambia.

Prevalence and risk factors for Q fever, spotted fever group rickettsioses, and typhus group rickettsioses in a pastoralist community of northern Tanzania, 2016-2017

BACKGROUND

In northern Tanzania, Q fever, spotted fever group (SFG) rickettsioses, and typhus group (TG) rickettsioses are common causes of febrile illness. We sought to describe the prevalence and risk factors for these zoonoses in a pastoralist community.

METHODS

Febrile patients ≥2 years old presenting to Endulen Hospital in the Ngorongoro Conservation Area were enrolled from August 2016 through October 2017. Acute and convalescent blood samples were collected, and a questionnaire was administered. Sera were tested by immunofluorescent antibody (IFA) IgG assays using Coxiella burnetii (Phase II), Rickettsia africae, and Rickettsia typhi antigens. Serologic evidence of exposure was defined by an IFA titre ≥1:64; probable cases by an acute IFA titre ≥1:128; and confirmed cases by a ≥4-fold rise in titre between samples. Risk factors for exposure and acute case status were evaluated.

RESULTS

Of 228 participants, 99 (43.4%) were male and the median (interquartile range) age was 27 (16-41) years. Among these, 117 (51.3%) had C. burnetii exposure, 74 (32.5%) had probable Q fever, 176 (77.2%) had SFG Rickettsia exposure, 134 (58.8%) had probable SFG rickettsioses, 11 (4.8%) had TG Rickettsia exposure, and 4 (1.8%) had probable TG rickettsioses. Of 146 participants with paired sera, 1 (0.5%) had confirmed Q fever, 8 (5.5%) had confirmed SFG rickettsioses, and none had confirmed TG rickettsioses. Livestock slaughter was associated with acute Q fever (adjusted odds ratio [OR] 2.54, 95% confidence interval [CI] 1.38-4.76) and sheep slaughter with SFG rickettsioses case (OR 4.63, 95% CI 1.08-23.50).

DISCUSSION

Acute Q fever and SFG rickettsioses were detected in participants with febrile illness. Exposures to C. burnetii and to SFG Rickettsia were highly prevalent, and interactions with livestock were associated with increased odds of illness with both pathogens. Further characterisation of the burden and risks for these diseases is warranted.

Aetiology of non-malaria acute febrile illness fever in children in rural Guinea-Bissau: a prospective cross-sectional investigation

Background

With growing use of parasitological tests to detect malaria and decreasing incidence of the disease in Africa; it becomes necessary to increase the understanding of causes of non-malaria acute febrile illness (NMAFI) towards providing appropriate case management. This research investigates causes of NMAFI in pediatric out-patients in rural Guinea-Bissau.

Methods

Children 0-5 years presenting acute fever (≥38°) or history of fever, negative malaria rapid diagnostic test (mRDT) and no signs of specific disease were recruited at the out-patient clinic of 3 health facilities in Bafatá province during 54 consecutive weeks (dry and rainy season). Medical history was recorded and blood, nasopharyngeal, stool and urine samples were collected and tested for the presence of 38 different potential aetiological causes of fever.

Results

Samples from 741 children were analysed, the protocol was successful in determining a probable aetiological cause of acute fever in 544 (73.61%) cases. Respiratory viruses were the most frequently identified pathogens, present in the nasopharynx samples of 435 (58.86%) cases, followed by bacteria detected in 167 (22.60%) samples. Despite presenting negative mRDTs, P. falciparum was identified in samples of 24 (3.25%) patients.

Conclusions

This research provides a description of the aetiological causes of NMAFI in West African context. Evidence of viral infections were more commonly found than bacteria or parasites.

Prevalence of fever of unidentified aetiology in East African adolescents and adults: a systematic review and meta-analysis

BACKGROUND

Primary health care settings and hospitals of low- and middle-income countries have few accessible diagnostic tools and limited laboratory and human resources capacity to identify multiple pathogens with high accuracy. In addition, there is a paucity of information on fever and its underlying aetiology in the adolescent and adult population in East Africa. The purpose of this study was to estimate the pooled prevalence of fever of unidentified aetiology among adolescent and adult febrile patients seeking health care in East Africa.

METHODS

We pursued a systematic review using readily available electronic databases (i.e. PubMed, Cumulative Index to Nursing & Allied Health Literature, Scopus, Cochrane Library and Web of Science) without language restriction from inception date of the respective databases to October 31, 2022. We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Identified studies were screened for relevance. Further analyses based on pre-set eligibility criteria were carried out for final inclusion. Two reviewers independently screened and extracted data. Risk of study bias was assessed. Meta-analysis of the prevalence of fever of unidentified aetiology was performed.

RESULTS

We identified 14,029 articles of which 25 were eligible for inclusion, reporting data from 8538 participants. The pooled prevalence of febrile cases with unidentified aetiology was 64% [95% confidence interval (CI): 51-77%, I² = 99.6%] among febrile adolescents and adults in East Africa. For the proportion of patients with identified aetiology, the studies documented bacterial pathogens (human bloodstream infections), bacterial zoonotic pathogens and arboviruses as the main non-malarial causative agents in East Africa.

CONCLUSIONS

Our study provides evidence that almost two-thirds of adolescent and adult febrile patients attending health care facilities in East Africa might receive inappropriate treatments due to unidentified potential life-threatening fever aetiology. Hence, we call for a comprehensive fever syndromic surveillance to broaden a consequential differential diagnosis of syndromic fever and to considerably improve the course of patients' disease and treatment outcomes.

Doxycycline responding illnesses in returning travellers with undifferentiated non-malaria fever: a European multicentre prospective cohort study

BACKGROUND

Diagnosis of undifferentiated non-malaria fevers (NMF) in returning travellers is a great challenge. Currently, there is no consensus about the use of empirical antibiotics in returning travellers with undifferentiated NMF. Although studies in endemic areas showed that a wide range of pathogens implicated in undifferentiated NMF are treatable with doxycycline, the role of doxycycline in returning travellers with fever still has to be explored.

METHODS

Prospective European multicentre cohort study of febrile international travellers (November 2017-November 2019). Immunological and molecular diagnostic techniques for doxycycline responding illnesses (DRI) agents such as Anaplasma phagocytophilum, spotted fever group Rickettsia spp., typhus group Rickettsia spp., Coxiella burnetii, Bartonella spp., Orientia tsutsugamushi, Borrelia miyamotoi, Borrelia recurrentis and Leptospira spp. were systematically performed in all patients with undifferentiated NMF. We estimated the prevalence and predictive factors of DRI in returning travellers with undifferentiated NMF.

RESULTS

Among 347 travellers with undifferentiated NMF, 106 (30·5%) were finally diagnosed with DRI. Only 57 (53·8%) of the 106 DRI infections were diagnosed by the standard of care. The main causes of DRI were: 55 (51·9%) Rickettsia spp., 16 (15·1%) C. burnetii; 15 (14·2%) Bartonella spp.; 13 (12·3%) Leptospira spp. and 10 (9·5%) A. phagocytophilum. The only predictive factor associated with DRI was presenting an eschar (aOR 39·52, 95%CI 4·85-322·18). Features of dengue such as retro-orbital pain (aOR 0·40, 95%CI 0·21-0·76) and neutropenia (aOR 0·41, 95%CI 0·21-0·79) were negatively associated with DRI.

CONCLUSIONS

Although DRI are responsible for 30% of undifferentiated NMF cases in travellers, those are seldom recognized during the first clinical encounter. Empirical treatment with doxycycline should be considered in returning travellers with undifferentiated fever and negative tests for malaria and dengue, particularly when presenting severe illness, predictive factors for rickettsiosis or no features of dengue.

Seroprevalence and Risk Factors for Q fever (Coxiella burnetii) Exposure in Smallholder Dairy Cattle in Tanzania

Q fever is a zoonotic disease, resulting from infection with Coxiella burnetii. Infection in cattle can cause abortion and infertility, however, there is little epidemiological information regarding the disease in dairy cattle in Tanzania. Between July 2019 and October 2020, a serosurvey was conducted in six high dairy producing regions of Tanzania. Cattle sera were tested for antibodies to C. burnetii using an indirect enzyme-linked immunosorbent assay. A mixed effect logistic regression model identified risk factors associated with C. burnetii seropositivity. A total of 79 out of 2049 dairy cattle tested positive with an overall seroprevalence of 3.9% (95% CI 3.06-4.78) across the six regions with the highest seroprevalence in Tanga region (8.21%, 95% CI 6.0-10.89). Risk factors associated with seropositivity included: extensive feeding management (OR 2.77, 95% CI 1.25-3.77), and low precipitation below 1000 mm (OR 2.76, 95% 1.37-7.21). The disease seroprevalence is relatively low in the high dairy cattle producing regions of Tanzania. Due to the zoonotic potential of the disease, future efforts should employ a "One Health" approach to understand the epidemiology, and for interdisciplinary control to reduce the impacts on animal and human health.

Antibody Prevalence and Risk Factors Associated with Rickettsia spp. in a Pediatric Cohort: SFGR Remains Underdiagnosed and Underreported in El Salvador

Spotted fever group rickettsioses (SFGR) are caused by a group of tick-borne pathogens that are increasing in incidence globally. These diseases are typically underreported and undiagnosed in low- and middle-income countries, and thus, have been classified as neglected bacterial pathogens. Countries with high poverty, low human development index score, and limited health infrastructure—like El Salvador in Central America—lack necessary surveillance for SFGR and other tick-borne pathogens. This paucity of baseline SFGR infection prevalence leaves vulnerable populations at risk of misdiagnosis. Further, tick-borne disease burdens in El Salvador are severely limited. To lay the foundation for tick-borne disease epidemiology in El Salvador, our team conducted two different enzyme-linked immunosorbent assays (ELISA) on banked human sera samples from a cohort of approximately 1000 pediatric participants from a high-risk vector-borne disease population. Eleven percent of all tested banked pediatric sera were positive for at least one ELISA assay at the time of enrollment: 10.7% were positive for only IgM antibodies (acute SFGR infection), and 2.5% were positive for IgG antibodies (a past SFGR infection). Older, male, children enrolled during the wet season, with a household history of infectious disease and higher maternal education level had higher odds of SFGR antibodies. Additionally, children from households with domestic poultry birds and previous knowledge of other vector-borne diseases had significantly reduced odds of SFGR antibodies. The large percentage of acute SFGR infections indicates that it continues to remain an underreported and undiagnosed issue in El Salvador and the Central American region. Much is still unknown regarding the complexity of the tick, animal host, and human host ecology transmission cycle of SFGR in El Salvador.

Lice and lice-borne diseases in humans in Africa: a narrative review

Lice are host-specific insects. Human lice include Pediculus humanus humanus (body lice) which are known to be vectors of serious human bacterial infectious diseases including epidemic typhus, relapsing fever, trench fever and plague; Pediculus humanus capitis (head lice) that frequently affect children; and Pthirus pubis, commonly known as crab lice. In Africa, human infections transmitted by lice remained poorly known and therefore, underestimated, perhaps due to the lack of diagnostic tools and professional knowledge. In this paper we review current knowledge of the microorganisms identified in human lice in the continent of Africa, in order to alert health professionals to the importance of recognising the risk of lice-related diseases.

Prospective cohort study reveals unexpected aetiologies of livestock abortion in northern Tanzania

Livestock abortion is an important cause of productivity losses worldwide and many infectious causes of abortion are zoonotic pathogens that impact on human health. Little is known about the relative importance of infectious causes of livestock abortion in Africa, including in subsistence farming communities that are critically dependent on livestock for food, income, and wellbeing. We conducted a prospective cohort study of livestock abortion, supported by cross-sectional serosurveillance, to determine aetiologies of livestock abortions in livestock in Tanzania. This approach generated several important findings including detection of a Rift Valley fever virus outbreak in cattle; high prevalence of C. burnetii infection in livestock; and the first report of Neospora caninum, Toxoplasma gondii, and pestiviruses associated with livestock abortion in Tanzania. Our approach provides a model for abortion surveillance in resource-limited settings. Our findings add substantially to current knowledge in sub-Saharan Africa, providing important evidence from which to prioritise disease interventions.

Individual and community-level factors of treatment-seeking behaviour among caregivers with febrile children in Ethiopia: A multilevel analysis

Background

Early diagnosis and treatment of childhood fever are essential for controlling disease progression and death. However, the Treatment-seeking behaviour of caregivers is still a significant challenge in rural parts of the African region. This study aimed to assess individual and community-level factors associated with treatment-seeking behaviours among caregivers of febrile under-five age children in Ethiopia.

Method

The recent Ethiopian Demographic and Health Survey data (EDHS 2016) was used for the study. The survey collected information among 1,354 under-five children who had a fever within two weeks before the survey. The data were extracted, cleaned, and recoded using STATA version 14. Multilevel logistic regressions were used to determine the magnitude and associated factors of treatment-seeking behaviour among caregivers with febrile children in Ethiopia. Four models were built to estimate both fixed and random effects of individual and community-level factors between cluster variations on treatment-seeking behaviour. The Adjusted Odds Ratios with 95% Confidence Intervals (CI) of the best-fitted model were reported at p<0.05.

Result

This study revealed that 491 (36.26%) caregivers seek treatment for their febrile children. Living in metropolitan and small peripheral regions, delivery at health institutions, being poorer, middle and richer wealth quintiles, having a child with diarrhoea, cough, short rapid breathing, and wasting were positively associated with treatment-seeking behaviour of caregivers.

Conclusion

The caregivers had poor treatment-seeking behaviour for their febrile children in Ethiopia. Health education programmers should emphasise the importance of seeking early treatment, taking action on childhood febrile illness signs.

Sero-epidemiological survey of Coxiella burnetii in livestock and humans in Tana River and Garissa counties in Kenya

Background

Coxiella burnetii is a widely distributed pathogen, but data on its epidemiology in livestock, and human populations remain scanty, especially in developing countries such as Kenya. We used the One Health approach to estimate the seroprevalance of C. burnetii in cattle, sheep, goats and human populations in Tana River county, and in humans in Garissa county, Kenya. We also identified potential determinants of exposure among these hosts.

Methods

Data were collected through a cross-sectional study. Serum samples were taken from 2,727 animals (466 cattle, 1,333 goats, and 928 sheep) and 974 humans and screened for Phase I/II IgG antibodies against C. burnetii using enzyme-linked immunosorbent assay (ELISA). Data on potential factors associated with animal and human exposure were collected using a structured questionnaire. Multivariable analyses were performed with households as a random effect to adjust for the within-household correlation of C. burnetii exposure among animals and humans, respectively.

Results

The overall apparent seroprevalence estimates of C. burnetii in livestock and humans were 12.80% (95% confidence interval [CI]: 11.57–14.11) and 24.44% (95% CI: 21.77–27.26), respectively. In livestock, the seroprevalence differed significantly by species (p < 0.01). The highest seroprevalence estimates were observed in goats (15.22%, 95% CI: 13.34-17.27) and sheep (14.22%, 95% CI: 12.04–16.64) while cattle (3.00%, 95% CI: 1.65–4.99) had the lowest seroprevalence. Herd-level seropositivity of C. burnetii in livestock was not positively associated with human exposure. Multivariable results showed that female animals had higher odds of seropositivity for C. burnetii than males, while for animal age groups, adult animals had higher odds of seropositivity than calves, kids or lambs. For livestock species, both sheep and goats had significantly higher odds of seropositivity than cattle. In human populations, men had a significantly higher odds of testing positive for C. burnetii than women.

Conclusions

This study provides evidence of livestock and human exposure to C. burnetii which could have serious economic implications on livestock production and impact on human health. These results also highlight the need to establish active surveillance in the study area to reduce the disease burden associated with this pathogen.

Q fever caused by Coxiella burnetii is a significant zoonotic disease that affects wildlife, domestic animals and humans. This study determined the prevalence of antibodies to C. burnetii in livestock (cattle, sheep, and goats) and human populations in arid and semi-arid areas of Kenya between December 2013 and February 2014. We also identified potential factors that were associated with exposure among the above-targeted hosts. Results from this study showed considerable exposure in both livestock and human populations. However, human exposure to this pathogen at the household level was not correlated with herd-level seropositivity. Further studies are needed to elucidate the transmission routes of this pathogen among humans.

Seroprevalence of brucellosis, Q fever and Rift Valley fever in domestic ruminants in Guinea in 2017-2019

BACKGROUND

Brucellosis, Q fever and Rift Valley fever are considered as Neglected Zoonotic Diseases (NZDs) leading to socioeconomic losses in livestock globally, and particularly in developing countries of Africa where they are under-reported. In this study, we evaluated the seroprevalence of these 3 zoonotic diseases in domestic ruminants in Guinea from 2017 to 2019. A total of 1357 sera, sampled from 463 cattle, 408 goats and 486 sheep, were collected in 17 Guinean prefectures and analyzed by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Cattle was the species with highest seroprevalence (5 to 20-fold higher than in small ruminants) for the three diseases. The seroprevalence of brucellosis, mostly focused in Western Guinea, was 11.0% (51 of 463) in cattle, 0.4% (2 in 486) in sheep while no specific antibodies were found in goats. Q fever, widespread across the country, was the most frequently detected zoonosis with a mean seroprevalence of 20.5% (95 in 463), 4.4% (18 in 408) and 2.3% (11 in 486) in cattle, goats and sheep, respectively. The mean seroprevalence of RVF was 16.4% (76 in 463) in cattle, 1.0% (4 in 408) in goats and 1.0% (5 in 486) in sheep. Among the samples 19.3% were seropositive for at least one of the three NZDs, 2.5% showed specific antibodies against at least two pathogens and 4 cattle (0.8%) were seropositive for all three pathogens. In cattle, adults over 3-years old and females presented a higher antibody seroprevalence for the three diseases, in congruence with putative exposure risk.

CONCLUSIONS

This study confirms the circulation of these three zoonotic pathogens in Guinea and highlights the need for implementing a syndromic surveillance of ruminant abortions by the Guinean veterinary authorities as well as for the screening of the human population at risk (veterinarians, breeders, slaughterers) in a One Health perspective.

"There are many fevers": Communities' perception and management of Febrile illness and its relationship with human animal interactions in South-Western Uganda

Diagnosing the causative agent of febrile illness in resource-limited countries is a challenge in part due to lack of adequate diagnostic infrastructure to confirm cause of infection. Most febrile illnesses (>60%) are non-malarial, with a significant proportion being zoonotic and likely from animal origins. To better characterize the pathways for zoonotic disease transmission and control in vulnerable communities, adequate information on the communities' experiences and lexicon describing fever, and their understanding and perceptions of risk pathways is required. We undertook an ethnographic study to understand behaviors, exposures, and attitudes toward fever at the community level. Our hope is to better elucidate areas of priority surveillance and diagnostic investment. A focused ethnography consisting of participant observation, informal conversations, 4 barazas (community meetings), and formal ethnographic interviews (13 Focus group discussions and 17 Key informant interviews) was conducted between April and November 2015 in Kasese and Hoima Districts in Uganda. Perception of illness and associated risk factors was heavily influenced by the predominant livelihood activity of the community. The term "fever" referred to multiple temperature elevating disease processes, recognized as distinct pathological occurrences. However, malaria was the illness often cited, treated, or diagnosed both at the health facilities and through self-diagnosis and treatment. As expected, fever is as an important health challenge affecting all ages. Recognition of malarial fever was consistent with a biomedical model of disease while non-malarial fevers were interpreted mainly through ethno etiological models of explanation. These models are currently being used to inform education and prevention strategies and treatment regimens toward the goal of improving patients' outcomes and confidence in the health system. Development of treatment algorithms that consider social, cultural, and economic contexts, especially where human-animal interaction is prevalent, should factor animal exposure and zoonotic illnesses as important differentials.

A systematic review and meta-analysis of the aetiological agents of non-malarial febrile illnesses in Africa

Background

The awareness of non-malarial febrile illnesses (NMFIs) has been on the rise over the last decades. Therefore, we undertook a systematic literature review and meta-analysis of causative agents of non-malarial fevers on the African continent.

Methodology

We searched for literature in African Journals Online, EMBASE, PubMed, Scopus, and Web of Science databases to identify aetiologic agents that had been reported and to determine summary estimates of the proportional morbidity rates (PMr) associated with these pathogens among fever patients.

Findings

A total of 133 studies comprising 391,835 patients from 25 of the 54 African countries were eligible. A wide array of aetiologic agents were described with considerable regional differences among the leading agents. Overall, bacterial pathogens tested from blood samples accounted for the largest proportion. The summary estimates from the meta-analysis were low for most of the agents. This may have resulted from a true low prevalence of the agents, the failure to test for many agents or the low sensitivity of the diagnostic methods applied. Our meta-regression analysis of study and population variables showed that diagnostic methods determined the PMr estimates of typhoidal Salmonella and Dengue virus. An increase in the PMr of Klebsiella spp. infections was observed over time. Furthermore, the status of patients as either inpatient or outpatient predicted the PMr of Haemophilus spp. infections.

Conclusion

The small number of epidemiological studies and the variety of NMFI agents on the African continent emphasizes the need for harmonized studies with larger sample sizes. In particular, diagnostic procedures for NMFIs should be standardized to facilitate comparability of study results and to improve future meta-analyses. Reliable NMFI burden estimates will inform regional public health strategies.

Previous systematic reviews have highlighted the research priorities of causative agents for non-malarial febrile illnesses by counting the number of publications attributed to an agent. However, proportional morbidity rates are calculated by dividing the number of cases with a specific disease (numerator) by the total number of diagnosed fever cases (denominator) and are better indicators of the relative importance of aetiological agents in a population. Therefore, we present the leading causes of non-malarial febrile illnesses in African patients in both healthcare and community settings. Preference is given to HIV-negative patients when data could be found. We also determined summary estimates of Brucella spp., Chikungunya virus, Dengue virus, Haemophilus spp., Klebsiella spp., Leptospira spp., non-typhoidal Salmonella spp., typhoidal Salmonella spp., Staphylococcus spp., and Streptococcus spp.

The wide array of aetiological agents causing febrile illnesses on the African continent does not only complicate malaria control programs but may also hamper response to epidemic and pandemic illnesses such as Ebola and COVID-19. The harmonisation of diagnostics and study designs will reduce between-study differences, which may result in better estimates of disease burden on the continent and in the different African regions. This information is important for Pan-African surveillance and control efforts.

Seroreactivity to Coxiella burnetii in an Agricultural Population and Prevalence of Coxiella burnetii Infection in Ticks of a Non-Endemic Region for Q Fever in South Korea

Coxiella burnetii infects humans and wild and domesticated animals. Although reported cases on Jeju Island, off the coast of South Korea, are rare, the region is considered to have a high potential for Q fever. We investigated the seroprevalence of antibodies to C. burnetii in 230 farmers living in ten rural areas on Jeju Island between January 2015 and December 2019. Blood samples were collected and examined for C. burnetii Phase I/II IgM and IgG antibodies. Trained researchers collected ticks from rural areas. Clone XCP-1 16S ribosomal RNA gene sequencing was performed to identify Coxiella species from the collected ticks. The overall seroprevalence of antibodies to C. burnetii in farmers was 35.7%. The seroprevalence was significantly higher in fruit farmers. Of the collected ticks, 5.4% (19/351) of the Haemaphysalis longicornis ticks harbored C. burnetti. A high seroprevalence of antibodies to C. burnetii was observed in this region of Jeju Island, confirming that C. burnetti is endemic. Physicians should thus consider Q fever in the differential diagnosis of patients that present with acute fever after participating in outdoor activities.

Utilization of Standard Method Performance Requirements for the Detection of Coxiella burnetii in Environmental Samples

BACKGROUND

Coxiella burnetii, the causative agent of Q fever, is a long-standing public health problem. Infected animals shed the organism, resulting in aerosol transmission to humans. This organism can potentially be used as a bioterrorism weapon and is on the Department of Health and Human Service Select Agent List. Assay development for detecting C. burnetii in environmental samples has been limited.

OBJECTIVE

We describe the use of Standard Method Performance Requirements (SMPR®) 2015.011 to detect Coxiella in air filters and liquids to validate additional environmental samples.

METHOD

SMPR 2015.011 was used to validate a real-time polymerase chain reaction (rtPCR) assay developed to detect C. burnetii DNA in powder samples submitted to the public health laboratory for biothreat analysis.

RESULTS

Our laboratory developed an assay to detect the icd gene of C. burnetii. The LOD for the assay was 33 gene copies per rtPCR reaction in buffer and 260 in each of the three separate powdered samples.

CONCLUSIONS

The SMPR 2015.011 allowed validation of an assay to detect Coxiella nucleic acid in an environmental sample. The assay was sensitive, robust, specific, and able to detect this select agent in powders.

HIGHLIGHTS

Development of detection assays for agents that are difficult to culture and have limited validation material available can be problematic for manufacturers. Using the SMPR 2015.011 developed for the detection of Coxiella as well as the SMPR 2016.012 for the detection of Variola, we demonstrated that assays can be appropriately validated using alternative approaches.

High Prevalence and New Genotype of Coxiella burnetii in Ticks Infesting Camels in Somalia

Coxiella burnetii is the causative agent of Q fever. It can infect animals, humans, and birds, as well as ticks, and it has a worldwide geographical distribution. To better understand the epidemiology of C. burnetii in Somalia, ticks infesting camels were collected from five different regions, including Bari, Nugaal, Mudug, Sool, and Sanaag, between January and March 2018. Collected ticks were tested for C. burnetii and Coxiella-like endosymbiont DNA by using IS1111, icd, and Com1-target PCR assays. Moreover, sequencing of the 16S-rRNA was conducted. Molecular characterization and typing were done by adaA-gene analysis and plasmid-type identification. Further typing was carried out by 14-marker Multi-Locus Variable-Number Tandem Repeats (MLVA/VNTR) analysis. The investigated ticks (n = 237) were identified as Hyalomma spp. (n = 227, 95.8%), Amblyomma spp. (n = 8, 3.4%), and Ripicephalus spp. (n = 2, 0.8%), and 59.1% (140/237) of them were positive for Coxiella spp. While Sanger sequencing and plasmid-type identification revealed a C. burnetii that harbours the QpRS-plasmid, MLVA/VNTR genotyping showed a new genotype which was initially named D21. In conclusion, this is the first report of C. burnetii in ticks in Somalia. The findings denote the possibility that C. burnetii is endemic in Somalia. Further epidemiological studies investigating samples from humans, animals, and ticks within the context of "One Health" are warranted.

Seroprevalence of Coxiella burnetii in patients presenting with acute febrile illness at Marigat District Hospital, Baringo County, Kenya

Q fever is not routinely diagnosed in Kenyan hospitals. This study reports on Q fever in patients presenting at Marigat District Hospital, Kenya, with febrile illness. ELISA was used to detect Coxiella burnetii phase antigens. Of 406 patients, 45 (11.1%) were judged to have acute disease (phase II IgM or IgG > phase I IgG), 2 (0.5%) were chronic (phase I IgG titer >800 or phase I IgG > phase II IgG), while 26 (6.4%) had previous exposure (phase I IgG titer <800). Age (6–10 years, p = 0.002) and contact with goats (p = 0.014) were significant risk factors. Compared to immunofluorescence antibody test, the sensitivity and specificity for phase I IgG were 84% and 98%, respectfully, 46% and 100% for phase II IgG and 35% and 89% for phase II IgM. It is concluded that the low sensitivity of phase II ELISA underestimated the true burden of acute Q fever in the study population.

Coxiella burnetii in Dromedary Camels (Camelus dromedarius): A Possible Threat for Humans and Livestock in North Africa and the Near and Middle East?

The "One Health" concept recognizes that human health is connected to animal health and to the ecosystems. Coxiella burnetii-induced human Q fever is one of the most widespread neglected zoonosis. The main animal reservoirs responsible for C. burnetii transmission to humans are domesticated ruminants, primarily goats, sheep, and cattle. Although studies are still too sparse to draw definitive conclusions, the most recent C. burnetii serosurvey studies conducted in herds and farms in Africa, North Africa, Arabian Peninsula, and Asia highlighted that seroprevalence was strikingly higher in dromedary camels (Camelus dromedarius) than in other ruminants. The C. burnetii seroprevalence in camel herds can reach more than 60% in Egypt, Saudi Arabia, and Sudan, and 70 to 80% in Algeria and Chad, respectively. The highest seroprevalence was in female camels with a previous history of abortion. Moreover, C. burnetii infection was reported in ticks of the Hyalomma dromedarii and Hyalomma impeltatum species collected on camels. Even if dromedary camels represent <3% of the domesticated ruminants in the countries of the Mediterranean basin Southern coast, these animals play a major socioeconomic role for millions of people who live in the arid zones of Africa, Middle East, and Asia. In Chad and Somalia, camels account for about 7 and 21% of domesticated ruminants, respectively. To meet the growing consumers demand of camel meat and milk (>5 million tons/year of both raw and pasteurized milk according to the Food and Agriculture Organization) sustained by a rapid increase of population (growth rate: 2.26-3.76 per year in North Africa), dromedary camel breeding tends to increase from the Maghreb to the Arabic countries. Because of possible long-term persistence of C. burnetii in camel hump adipocytes, this pathogen could represent a threat for herds and breeding farms and ultimately for public health. Because this review highlights a hyperendemia of C. burnetii in dromedary camels, a proper screening of herds and breeding farms for C. burnetii is urgently needed in countries where camel breeding is on the rise. Moreover, the risk of C. burnetii transmission from camel to human should be further evaluated.

Selected Endemic Zoonoses in Pigs Presenting for Slaughter in Kampala, Uganda

Leptospirosis, brucellosis, and Q fever (coxiellosis) are bacterial zoonoses that cause acute febrile illness in people as well as reproductive losses in pigs. Pig keeping is an increasingly important livelihood to millions of smallholder farmers in Uganda because of exponential increases in demand for pork. The prevalence of leptospirosis and Q fever in pigs is unknown, and the few studies of porcine brucellosis have estimated a range of seroprevalence. Therefore, we undertook a prevalence survey of leptospirosis, brucellosis, and Q fever in pigs using quantitative real-time PCR to determine the potential importance of these zoonoses to the growing pig sector in Uganda. Six hundred forty-nine pigs were sampled in 2015–2016 at an urban pork slaughterhouse. Ten percent of pigs (n = 68) had leptospiral DNA in either their kidney or reproductive tissue. In adjusted analyses, variables predictive of leptospiral status included female sex (odds ratio [OR]: 2.37, P < 0.01) and pigs sampled in March 2016 (OR: 2.23, P = 0.02) and October 2016 (OR: 0.30, P = 0.04). DNA fingerprinting revealed circulation of at least four distinct serovars in these pigs. Brucella spp. and Coxiella burnetii DNA were not detected in any sampled pig. This is the first report of widespread circulation of pathogenic Leptospira spp. in pigs in Uganda, suggesting that leptospirosis likely has a greater impact on the health of pigs than was previously recognized. Pig farmers, pig traders, and slaughterhouse workers may be at greatest occupational risk because of their direct contact with infective leptospires in aborted fetuses, bodily fluids, and other tissues.

Optimization and Evaluation of a Multiplex Quantitative PCR Assay for Detection of Nucleic Acids in Human Blood Samples from Patients with Spotted Fever Rickettsiosis, Typhus Rickettsiosis, Scrub Typhus, Monocytic Ehrlichiosis, and Granulocytic Anaplasmosis

Spotted fever group rickettsioses (SFGR), typhus group rickettsioses (TGR), scrub typhus (caused by Orientia tsutsugamushi), ehrlichiosis, and anaplasmosis often present as undifferentiated fever but are not treated by agents (penicillins and cephalosporins) typically used for acute febrile illness. Inability to diagnose these infections when the patient is acutely ill leads to excess morbidity and mortality. Failure to confirm these infections retrospectively if a convalescent blood sample is not obtained also impairs epidemiologic and clinical research. We designed a multiplex real-time quantitative PCR (qPCR) assay to detect SFGR, TGR, O. tsutsugamushi, and infections caused by Anaplasma phagocytophilum and Ehrlichia chaffeensis with the ompA, 17-kDa surface antigen gene, tsa56, msp2 (p44), and vlpt gene targets, respectively. Analytical sensitivity was ≥2 copies/μl (linear range, 2 to 2 × 10⁵) and specificity was 100%. Clinical sensitivities for SFGR, TGR, and O. tsutsugamushi were 25%, 20%, and 27%, respectively, and specificities were 98%, 99%, and 100%, respectively. Clinical sensitivities for A. phagocytophilum and E. chaffeensis were 93% and 84%, respectively, and specificities were 99% and 98%, respectively. This multiplex qPCR assay could support early clinical diagnosis and treatment, confirm acute infections in the absence of a convalescent-phase serum sample, and provide the high-throughput testing required to support large clinical and epidemiologic studies. Because replication of SFGR and TGR in endothelial cells results in very low bacteremia, optimal sensitivity of qPCR for these rickettsioses will require use of larger volumes of input DNA, which could be achieved by improved extraction of DNA from blood and/or extraction of DNA from a larger initial volume of blood.

Rickettsia africae an Agent of African Tick Bite Fever in Ticks Collected from Domestic Animals in Eastern Cape, South Africa

Background: Ticks transmit a plethora of pathogens of zoonotic implications. Their distribution, diversity and the pathogens they transmit differ from one ecological location to another. Rickettsia africae is the agent of African tick bite fever found in South Africa, a zoonotic infection that is frequently reported among travelers who have visited many sub-Saharan African countries where the pathogen is prevalent. Methods: Ticks were collected from domestic animals in Raymond Nkandla Municipality, Eastern Cape, South Africa. The ticks were identified morphologically prior to DNA extraction followed by molecular identification of randomly selected ticks from the morphologically delineated groups. To assess for the presence of tick-borne pathogens belonging to Rickettsia spp. by PCR (polymerase chain reaction), we used specific primer pairs targeting the gltA, ompA and ompB genes. The selected amplified ticks, all positive ompB and forty three ompA amplicons were sequenced in a commercial sequencing facility. The obtained nucleotide sequences were edited and subjected to BLASTn for homology search and phylogenetic analyses were performed with MEGA 7 Version for genetic relationships with curated reference sequences in GenBank. Results: A total of 953 ticks collected in the study were delineated into three genera consisting of Amblyomma, Rhipicephalus and Hyalomma in decreasing order of abundance. The presence of rickettsial DNA was detected in 60/953 (6.3%) from the three genera of ticks screened. Genetic analyses of the DNA sequences obtained showed that they have phylogenetic relationship to members of the spotted fever group rickettsiae with R. africae, being the predominant SFGR (spotted fever group rickettsiae) detected in the screened ticks. Conclusion: This report shows that R. africae is the predominant spotted fever group rickettsiae in ticks collected from domestic animals in the study area and the human health impacts are not known.

Selection of Diagnostic Cutoffs for Murine Typhus IgM and IgG Immunofluorescence Assay: A Systematic Review

Murine typhus is a neglected but widespread infectious disease that results in acute fever. The immunofluorescence assay (IFA) is the "gold standard" to identify IgM or IgG antibodies, although there is a lack of standardization in methodologies. The objective of this review is to summarize 1) the differences in published methodologies, 2) the diagnostic cutoff titers, and 3) the justification of diagnostic cutoffs. Searches were performed by combining the following search terms: "murine typhus," "rickettsia typhi," "immunofluorescence," "IFA," and "serologic" with restrictions (i.e., "rickettsia typhi" or "murine typhus," and "IFA" or "immunofluorescence," or "serologic*"). The search identified 78 studies that used IFA or immunoperoxidase assay (IIP) antibody cutoffs to diagnose murine typhus, 39 of which were case series. Overall, 45 studies (57.7%) provided little to no rationale as to how the cutoff was derived. Variation was seen locally in the cutoff titers used, but a 4-fold or greater increase was often applied. The cutoffs varied depending on the antibody target. No consensus was observed in establishing a cutoff, or for a single-value diagnostic cutoff. In conclusion, there is a lack of consensus in the establishment of a single-value cutoff. Further studies will need to be executed at each distinct geographic location to identify region-specific cutoffs, while also considering background antibody levels to distinguish between healthy and infected patients.

Microbial Safety of Milk Production and Fermented Dairy Products in Africa

In Africa, milk production, processing and consumption are integral part of traditional food supply, with dairy products being a staple component of recommended healthy diets. This review provides an overview of the microbial safety characteristics of milk production and fermented dairy products in Africa. The object is to highlight the main microbial food safety hazards in the dairy chain and to propose appropriate preventive and control measures. Pathogens of public health concern including Mycobacterium bovis, Brucella abortus and Coxiella burnettii, which have largely been eradicated in many developed nations, still persist in the dairy chain in Africa. Factors such as the natural antimicrobial systems in milk and traditional processing technologies, including fermentation, heating and use of antimicrobial additives, that can potentially contribute to microbial safety of milk and dairy products in Africa will be discussed. Practical approaches to controlling safety hazards in the dairy chain in Africa have been proposed. Governmental regulatory bodies need to set the necessary national and regional safety standards, perform inspections and put measures in place to ensure that the standards are met, including strong enforcement programs within smallholder dairy chains. Dairy chain actors would require upgraded knowledge and training in preventive approaches such as good agricultural practices (GAP), hazard analysis and critical control points (HACCP) design and implementation and good hygienic practices (GHPs). Food safety education programs should be incorporated into school curricula, beginning at the basic school levels, to improve food safety cognition among students and promote life-long safe food handling behaviour.

Case Report: Two Cases of Acute Q Fever from the Same Family Who Returned from Malawi to Japan

In July 2018, acute Q fever (AQF) was diagnosed in two Japanese individuals from the same family. They returned to Japan from Malawi, where the epidemiology of AQF is unknown. A child presented to the hospital with high-grade fever without any symptoms, and a mother presented with fever and dry cough. Paired serum antiphase Ⅱ IgM and IgG significantly elevated in the convalescent phase in both cases. Coxiella burnetii gene (IS1111) was detected from the mother's blood sample. They had no reported direct animal contact, but the onset of symptoms coincided with the dry season in Malawi, which may have facilitated environmental dispersal. These cases may serve as an alert for high-risk people to possible AQF spread and underdiagnosis in Malawi.

Prevalence of plasmodium, leptospira and rickettsia species in Northern Tanzania: a community based survey

BACKGROUND

The overlap of symptoms, geographic and seasonal co-occurrence of Plasmodium, Leptospira and Rickettsia infections makes malaria diagnosis difficult, increasing the chances of misdiagnosis. The paucity of data on the prevalence Plasmodium, Leptospira and Rickettsia infections contributes to an overly diagnosis of malaria. We aimed to determine the prevalence and distribution of Plasmodium, Leptospira and Rickettsia infections in northern Tanzania.

METHODS

A community based, cross sectional survey was conducted in two sites in Northern Tanzania. PCR was used to detect Plasmodium, Leptospira and Rickettsia infections.

RESULTS

The prevalence of P. falciparum and Leptospira spp were 31/128 (24.2%) and 3/128 (2.3%), respectively. No Rickettsia infection was detected in any of the two sites. Taking study sites separately, Plasmodium infection was detected in 31/63(49.2%) of participants in Bondo while Leptospira infection was detected in 3/65(4.6%) of participants in Magugu. Plasmodium was not detected in Magugu while no Leptospira infections were detected in Bondo. Fever was significantly associated with Plasmodium infection (χ2= 12.44, p<0.001) and age (χ2=17.44, p=0.000).

CONCLUSION

Results from this study indicate Plasmodium infection as the main cause of fever in the studied sites. While Plasmodium and Leptospira contribute to fevers, Rickettsia infection is an insignificant cause of fever in Northern Tanzania.

Etiology of Sepsis in Uganda Using a Quantitative Polymerase Chain Reaction-based TaqMan Array Card

Background

Knowledge of causes of sepsis in sub-Saharan Africa is limited. A better understanding of the microbiology of bloodstream infections could improve outcomes.

Methods

We used a quantitative polymerase chain reaction (qPCR)-based TaqMan Array Card (TAC) to directly test for 43 targets from whole blood. We analyzed 336 cryopreserved specimens from adult Ugandans with sepsis enrolled in a multisite study; 84% were infected with human immunodeficiency virus. We compared qPCR TAC results with blood culture and determined the association of qPCR with study participant outcomes using logistic regression.

Results

The most frequently detected targets were cytomegalovirus (CMV, n = 139, 41%), Mycobacterium tuberculosis (TB, n = 70, 21%), Plasmodium (n = 35, 10%), and Streptococcus pneumoniae (n = 31, 9%). Diagnostic performance varied by target with qPCR sensitivity averaging 61 ± 28% and specificity 98 ± 3% versus culture. In multivariable analysis, independent factors associated with in-hospital mortality included CMV viremia (adjusted odds ratio [aOR] 3.2, 95% confidence interval [CI], 1.8-5.5; p < .01) and TB qPCR-positivity, whether blood culture-positive (aOR 4.6, 95% CI, 2.1-10.0; p < .01) or blood culture-negative (aOR 2.9, 95% CI, 1.2-6.9; p = .02).

Conclusions

Using qPCR TAC on direct blood specimens, CMV and TB were the most commonly identified targets and were independently associated with increased in-hospital mortality. qPCR TAC screening of blood for multiple targets may be useful to guide triage and treatment of sepsis in sub-Saharan Africa.

The epidemiology, characteristics and outbreaks of human leptospirosis and the association with animals in Taiwan, 2007-2014: A nationwide database study

BACKGROUND

Leptospirosis (LS) is a neglected tropical zoonosis of global importance. A nationwide investigation of characteristics, epidemiology, risk factors and outbreak is crucial for awareness of this disease.

METHODS

A nationwide database of reported LS cases from October 2007 to December 2014 obtained from the Centers for Disease Control, Taiwan, was analysed. Geographic information system software was used to map the distribution of confirmed LS cases and pigs. Cross-matching with the databases of Q fever, scrub typhus and murine typhus was conducted to identify possible coinfections.

RESULTS

A total of 10,917 reported cases of LS were recorded in the database, which included 665 (6.1%) confirmed LS and 10,252 (93.9%) non-confirmed LS cases. The major residences of confirmed LS were the Kaohsiung-Pingtung (248, 37.3%) and Taipei (174, 26.2%) regions. The average annual incidence was 0.4/100,000 people. Compared with non-confirmed LS cases, confirmed LS cases had significantly higher percentages of male gender (83.6% vs. 67.9%, p < .001), high-risk occupations (farmer, animal husbandry or veterinarian) (24.8% vs. 13.7%, p < .001), residence in the Kaohsiung-Pingtung region (37.3% vs. 19.6%, p < .001) and exposure to rats (8.6% vs. 4.9%, p = .001) or pigs (9.4% vs. 1.9%, p < .001) but a lower mean age (47.8 ± 15.1 vs. 51.±18.5 years old). Rat and pig exposure trends were found in the northern and southern regions, respectively. Distribution of LS was consistent with pigs, and one outbreak associated with flooding and pigs occurred in the Pingtung region in 2009. Twenty-three and four patients with LS were coinfected with scrub typhus and Q fever, respectively.

CONCLUSIONS

LS is an endemic disease in Taiwan, particularly in the Kaohsiung-Pingtung and Taipei regions. High-risk occupations and animal exposure history are important for the clinical presumptive diagnosis of LS, particularly for rats in northern Taiwan and pigs in southern Taiwan. Although uncommon, clinicians should be aware of coinfection of LS with endemic rickettsial diseases.

Sensitivity of C-reactive protein for the identification of patients with laboratory-confirmed bacterial infections in northern Tanzania

OBJECTIVE

Identifying febrile patients requiring antibacterial treatment is challenging, particularly in low-resource settings. In South-East Asia, C-reactive protein (CRP) has been demonstrated to be highly sensitive and moderately specific in detecting bacterial infections and to safely reduce unnecessary antibacterial prescriptions in primary care. As evidence is scant in sub-Saharan Africa, we assessed the sensitivity of CRP in identifying serious bacterial infections in Tanzania.

METHODS

Samples were obtained from inpatients and outpatients in a prospective febrile illness study at two hospitals in Moshi, Tanzania, 2011-2014. Bacterial bloodstream infections (BSI) were established by blood culture, and bacterial zoonotic infections were defined by ≥4 fold rise in antibody titre between acute and convalescent sera. The sensitivity of CRP in identifying bacterial infections was estimated using thresholds of 10, 20 and 40 mg/l. Specificity was not assessed because determining false-positive CRP results was limited by the lack of diagnostic testing to confirm non-bacterial aetiologies and because ascertaining true-negative cases was limited by the imperfect sensitivity of the diagnostic tests used to identify bacterial infections.

RESULTS

Among 235 febrile outpatients and 569 febrile inpatients evaluated, 31 (3.9%) had a bacterial BSI and 61 (7.6%) had a bacterial zoonosis. Median (interquartile range) CRP values were 173 (80-315) mg/l in bacterial BSI, and 108 (31-208) mg/l in bacterial zoonoses. The sensitivity (95% confidence intervals) of CRP was 97% (83%-99%), 94% (79%-98%) and 90% (74%-97%) for identifying bacterial BSI, and 87% (76%-93%), 82% (71%-90%) and 72% (60%-82%) for bacterial zoonoses, using thresholds of 10, 20 and 40 mg/l, respectively.

CONCLUSION

C-reactive protein was moderately sensitive for bacterial zoonoses and highly sensitive for identifying BSIs. Based on these results, operational studies are warranted to assess the safety and clinical utility of CRP for the management of non-malaria febrile illness at first-level health facilities in sub-Saharan Africa.

Fever, bacterial zoonoses, and One Health in sub-Saharan Africa

Although often underappreciated, a number of bacterial zoonoses are endemic in Africa. Of these, brucellosis, leptospirosis, Q fever, and rickettsioses are responsible for a substantial proportion of febrile illness among patients seeking hospital care. In this paper, we discuss the aetiology, epidemiology, clinical presentation, diagnosis, treatment and prevention of these bacterial zoonoses. To prevent and control bacterial zoonoses, strategies targeting both animals and humans are crucial. These may lead to better outcomes than strategies based exclusively on treatment of human infections. Such strategies are referred to as the 'One Health' approach; the collaborative effort of multiple disciplines to attain optimal health for people, animals and the environment.

Systematic Review of Important Bacterial Zoonoses in Africa in the Last Decade in Light of the 'One Health' Concept

Zoonoses present a major public health threat and are estimated to account for a substantial part of the infectious disease burden in low-income countries. The severity of zoonotic diseases is compounded by factors such as poverty, living in close contact with livestock and wildlife, immunosuppression as well as coinfection with other diseases. The interconnections between humans, animals and the environment are essential to understand the spread and subsequent containment of zoonoses. We searched three scientific databases for articles relevant to the epidemiology of bacterial zoonoses/zoonotic bacterial pathogens, including disease prevalence and control measures in humans and multiple animal species, in various African countries within the period from 2008 to 2018. The review identified 1966 articles, of which 58 studies in 29 countries met the quality criteria for data extraction. The prevalence of brucellosis, leptospirosis, Q fever ranged from 0–40%, 1.1–24% and 0.9–28.2%, respectively, depending on geographical location and even higher in suspected outbreak cases. Risk factors for human zoonotic infection included exposure to livestock and animal slaughters. Dietary factors linked with seropositivity were found to include consumption of raw milk and locally fermented milk products. It was found that zoonoses such as leptospirosis, brucellosis, Q fever and rickettsiosis among others are frequently under/misdiagnosed in febrile patients seeking treatment at healthcare centres, leading to overdiagnoses of more familiar febrile conditions such as malaria and typhoid fever. The interactions at the human–animal interface contribute substantially to zoonotic infections. Seroprevalence of the various zoonoses varies by geographic location and species. There is a need to build laboratory capacity and effective surveillance processes for timely and effective detection and control of zoonoses in Africa. A multifaceted ‘One Health’ approach to tackle zoonoses is critical in the fight against zoonotic diseases. The impacts of zoonoses include: (1) Humans are always in contact with animals including livestock and zoonoses are causing serious life-threatening infections in humans. Almost 75% of the recent major global disease outbreaks have a zoonotic origin. (2) Zoonoses are a global health challenge represented either by well-known or newly emerging zoonotic diseases. (3) Zoonoses are caused by all-known cellular (bacteria, fungi and parasites) and noncellular (viruses or prions) pathogens. (4) There are limited data on zoonotic diseases from Africa. The fact that human health and animal health are inextricably linked, global coordinated and well-established interdisciplinary research efforts are essential to successfully fight and reduce the health burden due to zoonoses. This critically requires integrated data from both humans and animals on zoonotic diseases.

The sero-epidemiology of Coxiella burnetii (Q fever) across livestock species and herding contexts in Laikipia County, Kenya

Coxiella burnetii, the causative agent of Query fever (Q fever), is among the most highly infectious zoonotic pathogens transmitted among livestock, with chronic effects challenging to veterinary and medical detection and care systems. Transmission among domestic livestock species can vary regionally due to herd management practices that determine which livestock species are raised, whether or not livestock are in contact with wildlife, and the susceptibility of these livestock to infection. To explore how different livestock management practices are associated with the risk of infection in multispecies environments, we carried out a comparative study of three types of herd management systems in the central Kenyan county of Laikipia: agro-commercial, mixed conservancy/commercial, and smallholder ranches. We tested C. burnetii antibody seroprevalence in four common livestock species. Across all management types, the highest seroprevalence was in camels (20%), followed by goats (18%), sheep (13%), and cattle (6%). We observed a lower odds of testing seropositive for young compared to adult animals (adjusted OR = 0.44 [95% CI 0.24, 0.76]), and for males compared to females (adjusted OR = 0.52 [95% CI 0.33, 0.80]). Animals from mixed conservancy/commercial and smallholder operations had a higher odds of testing seropositive compared to animals from agro-commercial ranches (adjusted OR = 5.17 [95% CI 2.71, 10.44] and adjusted OR = 2.21 [95% CI 1.17, 4.43] respectively). These data suggest that herd management practices might affect the transmission dynamics of C. burnetiiin arid African ecosystems like those seen in Kenya where several transmission modes are possible, risk of drought has promoted new livestock species such as camels, and multiple wildlife species may co-occur with livestock on the landscape. Further longitudinal studies are needed to disentangle the mechanisms underlying these patterns, and further explore transmission patterns between wildlife, domestic animal, and human populations.

The epidemiology of febrile illness in sub-Saharan Africa: implications for diagnosis and management

BACKGROUND

Fever is among the most common symptoms of people living in Africa, and clinicians are challenged by the similar clinical features of a wide spectrum of potential aetiologies.

AIM

To summarize recent studies of fever aetiology in sub-Saharan Africa focusing on causes other than malaria.

SOURCES

A narrative literature review by searching the MEDLINE database, and recent conference abstracts.

CONTENT

Studies of multiple potential causes of fever are scarce, and for many participants the infecting organism remains unidentified, or multiple co-infecting microorganisms are identified, and establishing causation is challenging. Among ambulatory patients, self-limiting arboviral infections and viral upper respiratory infections are common, occurring in up to 60% of children attending health centres. Among hospitalized patients there is a high prevalence of potentially fatal infections requiring specific treatment. Bacterial bloodstream infection and bacterial zoonoses are major causes of fever. In recent years, the prevalence of antimicrobial resistance among bacterial isolates has increased, notably with spread of extended spectrum β-lactamase-producing Enterobacteriaceae and fluoroquinolone-resistant Salmonella enterica. Among those with human immunodeficiency virus (HIV) infection, Mycobacterium tuberculosis bacteraemia has been confirmed in up to 34.8% of patients with sepsis, and fungal infections such as cryptococcosis and histoplasmosis remain important.

IMPLICATIONS

Understanding the local epidemiology of fever aetiology, and the use of diagnostics including malaria and HIV rapid-diagnostic tests, guides healthcare workers in the management of patients with fever. Current challenges for clinicians include assessing which ambulatory patients require antibacterial drugs, and identifying hospitalized patients infected with organisms that are not susceptible to empiric antibacterial regimens.

Study on causes of fever in primary healthcare center uncovers pathogens of public health concern in Madagascar

BACKGROUND

The increasing use of malaria diagnostic tests reveals a growing proportion of patients with fever but no malaria. Clinicians and health care workers in low-income countries have few tests to diagnose causes of fever other than malaria although several diseases share common symptoms. We propose here to assess etiologies of fever in Madagascar to ultimately improve management of febrile cases.

METHODOLOGY

Consenting febrile outpatients aged 6 months and older were recruited in 21 selected sentinel sites throughout Madagascar from April 2014 to September 2015. Standard clinical examinations were performed, and blood and upper respiratory specimens were taken for rapid diagnostic tests and molecular assays for 36 pathogens of interest for Madagascar in terms of public health, regardless of clinical status.

PRINCIPAL FINDINGS

A total of 682 febrile patients were enrolled. We detected at least one pathogen in 40.5% (276/682) of patients and 6.2% (42/682) with co-infections. Among all tested patients, 26.5% (181/682) had at least one viral infection, 17.0% (116/682) had malaria and 1.0% (7/682) presented a bacterial or a mycobacterial infection. None or very few of the highly prevalent infectious agents in Eastern Africa and Asia were detected in this study, such as zoonotic bacteria or arboviral infections.

CONCLUSIONS

These results raise questions about etiologies of fever in Malagasy communities. Nevertheless, we noted that viral infections and malaria still represent a significant proportion of causes of febrile illnesses. Interestingly our study allowed the detection of pathogens of public health interest such as Rift Valley Fever Virus but also the first case of laboratory-confirmed leptospirosis infection in Madagascar.

Coxiella burnetii Detected in Tick Samples from Pastoral Communities in Kenya

Ticks are important disease vectors in Kenya with documented evidence of carriage of zoonotic pathogens. Coxiella burnetii is an important tick-borne pathogen that is underreported in Kenya and yet this infection likely contributes to undiagnosed febrile disease in pastoral communities. Archived human blood (278) and tick pool samples (380) collected from five pastoral communities in Kenya were screened for C. burnetii by PCR using primers targeting the transposon-like IS1111 region. All the human blood samples were negative for C. burnetii DNA. However, C. burnetii was detected in 5.53% (21/380) of the tick pools tested. Four of the twenty-one PCR positive samples were sequenced. The findings indicate that Coxiella burnetii was not present in the human blood samples tested. However, C. burnetii was detected in ticks from Mai Mahiu, Marigat, Ijara, Isiolo, and Garissa indicating a natural infection present in the tick vector that poses a risk to livestock and humans in these communities.

Prevalence of Tick-Borne Pathogens from Ticks Collected from Cattle and Wild Animals in Tanzania in 2012

This study was aimed to disclose the prevalence rate of tick-borne pathogens from ticks collected from cattle and wild animals in Tanzania in 2012. Ticks were collected from slaughtered cattle and dead wild animals from November 5 to December 23, 2012 and identified. PCR for detecting Anaplasmataceae, Piroplamidae, Rickettsiaceae, Borrelia spp., and Coxiella spp. were done. Among those tested, Rickettsiaceae, Piroplasmidae, and Anaplasmataceae, were detected in ticks from the 2 regions. Rickettsiaceae represented the major tick-borne pathogens of the 2 regions. Ticks from animals in Maswa were associated with a higher pathogen detection rate compared to that in ticks from Iringa. In addition, a higher pathogen detection rate was observed in ticks infesting cattle than in ticks infesting wild animals. All examined ticks of the genus Amblyomma were infected with diverse pathogens. Ticks of the genera Rhipicephalus and Hyalomma were infected with 1 or 2 pathogens. Collectively, this study provides important information regarding differences in pathogen status among various regions, hosts, and tick species in Tanzania. Results in this study will affect the programs to prevent tick-borne diseases (TBD) of humans and livestock in Tanzania.

Prevalence of Selected Zoonotic Diseases and Risk Factors at a Human-Wildlife-Livestock Interface in Mpumalanga Province, South Africa

A lack of surveillance and diagnostics for zoonotic diseases in rural human clinics limits clinical awareness of these diseases. We assessed the prevalence of nine zoonotic pathogens in a pastoral, low-income, HIV-endemic community bordering wildlife reserves in South Africa. Two groups of participants were included: malaria-negative acute febrile illness (AFI) patients, called febrilers, at three clinics (n = 74) and second, farmers, herders, and veterinary staff found at five government cattle dip-tanks, called dip-tanksters (n = 64). Blood samples were tested using one PCR (Bartonella spp.) and eight antibody-ELISAs, and questionnaires were conducted to assess risk factors. Seventy-seven percent of febrilers and 98% of dip-tanksters had at least one positive test. Bartonella spp. (PCR 9.5%), spotted fever group (SFG) Rickettsia spp. (IgM 24.1%), Coxiella burnetii. (IgM 2.3%), and Leptospira spp. (IgM 6.8%) were present in febrilers and could have been the cause of their fever. Dip-tanksters and febrilers had evidence of past infection to Rickettsia spp. (IgG 92.2% and 63.4%, respectively) and C. burnetii (IgG 60.9% and 37.8%, respectively). No Brucella infection or current Bartonella infection was found in the dip-tanksters, although they had higher levels of recent exposure to Leptospira spp. (IgM 21.9%) compared to the febrilers. Low levels of West Nile and Sindbis, and no Rift Valley fever virus exposure were found in either groups. The only risk factor found to be significant was attending dip-tanks in febrilers for Q fever (p = 0.007). Amoxicillin is the local standard treatment for AFI, but would not be effective for Bartonella spp. infections, SFG rickettsiosis, Q fever infections, or the viral infections. There is a need to revise AFI treatment algorithms, educate medical and veterinary staff about these pathogens, especially SFG rickettsiosis and Q fever, support disease surveillance systems, and inform the population about reducing tick and surface water contact.

Development of a loop-mediated isothermal amplification (LAMP) assay for rapid screening of ticks and fleas for spotted fever group rickettsia

Background

The importance of tick and flea-borne rickettsia infections is increasingly recognized worldwide. While increased focus has shifted in recent years to the development of point-of-care diagnostics for various vector-borne diseases in humans and animals, little research effort has been devoted to their integration into vector surveillance and control programs, particularly in resource-challenged countries. One technology which may be helpful for large scale vector surveillance initiatives is loop-mediated isothermal amplification (LAMP). The aim of this study was to develop a LAMP assay to detect spotted fever group (SFG) rickettsia DNA from field-collected ticks and fleas and compare with published end-point PCR results.

Methodology/Principal findings

A Spotted Fever Group rickettsia-specific loop-mediated isothermal amplification (SFGR-LAMP) assay was developed using primers based on a region of the R. rickettsii 17kDa protein gene. The sensitivity, specificity, and reproducibility of the assay were evaluated. The assay was then compared with the results of end-point PCR assays for pooled tick and flea samples obtained from field-based surveillance studies. The sensitivity of the SFGR-LAMP assay was 0.00001 ng/μl (25μl volume) which was 10 times more sensitive than the 17kDa protein gene end-point PCR used as the reference method. The assay only recognized gDNA from SFG and transitional group (TRG) rickettsia species tested but did not detect gDNA from typhus group (TG) rickettsia species or closely or distantly related bacterial species. The SFGR-LAMP assay detected the same positives from a set of pooled tick and flea samples detected by end-point PCR in addition to two pooled flea samples not detected by end-point PCR.

Conclusions/significance

To our knowledge, this is the first study to develop a functional LAMP assay to initially screen for SFG and TRG rickettsia pathogens in field-collected ticks and fleas. With a high sensitivity and specificity, the results indicate the potential use as a field-based surveillance tool for tick and flea-borne rickettsial pathogens in resource-challenged countries.

Development and Clinical Validation of a Multiplex Real-Time Quantitative PCR Assay for Human Infection by Anaplasma phagocytophilum and Ehrlichia chaffeensis

Background: Human granulocytic anaplasmosis (HGA), caused by Anaplasma phagocytophilum, and human monocytic ehrlichiosis (HME), caused by Ehrlichia chaffeensis, often present as undifferentiated fever but are not treated by typical empiric regimens for acute febrile illness. Their role as agents of vector-borne febrile disease in tropical regions is more poorly studied than for other rickettsial infections. Limitations in diagnosis have impaired epidemiologic and clinical research and needless morbidity and mortality occur due to untreated illness. Methods: We designed and clinically validated a multiplex real-time quantitative PCR assay for Anaplasma phagocytophilum and Ehrlichia chaffeensis using samples confirmed by multiple gold-standard methods. Results: Clinical sensitivity and specificity for A. phagocytophilum were 100% (39/39) and 100% (143/143), respectively, and for E. chaffeensis 95% (20/21) and 99% (159/161), respectively. Conclusions: These assays could support early diagnosis and treatment as well as the high-throughput testing required for large epidemiologic studies.

Rickettsial Infections and Q Fever Amongst Febrile Patients in Bhutan

There is limited evidence of rickettsial diseases in Bhutan. We explored the contribution of rickettsioses as a cause of undifferentiated febrile illness in patients presenting to 14 Bhutanese hospitals from October 2014 to June 2015. Obvious causes of fever were excluded clinically. Clinico-demographic information and acute blood samples were collected. Samples were tested by immunofluorescence assay (IFA) and qPCR against scrub typhus group (STG), spotted fever group (SFG) and typhus group (TG) rickettsiae, and Q fever (QF). Of the 1044 patients, 539 (51.6%) were female and the mean age was 31.5 years. At least 159 (15.2%) of the patients had evidence of a concurrent rickettsial infection. Of these, 70 (6.7%), 46 (4.4%), 4 (0.4%), and 29 (2.8%) were diagnosed as acute infections with STG, SFG, TG, and QF respectively. Ten (1.0%) patients were seropositive for both SFG and TG. Seven of the 70 STG patients were positive by qPCR. Eschar (p < 0.001), myalgia (p = 0.003), and lymphadenopathy (p = 0.049) were significantly associated with STG, but no specific symptoms were associated with the other infections. Disease incidences were not different between age groups, genders, occupations, and districts, except for students with significantly lower odds of infection with STG (OR = 0.43; 95% CI = 0.20, 0.93; p = 0.031). Rickettsioses were responsible for at least 15% of undifferentiated febrile illnesses in Bhutan, scrub typhus being the commonest. Health authorities should ensure that health services are equipped to manage these infections.

Rickettsia diversity in southern Africa: A small mammal perspective

Worldwide, including Africa, rickettsioses are recognized as emerging or re-emerging infections. To date, little is known about the diversity of Rickettsia species that are naturally associated with small mammals in southern Africa. The aim of the study was to screen a diversity of small mammals for the presence of rickettsial DNA. Animals were trapped at 38 localities in South Africa and Namibia. In total, 1616 ear-tissue samples from 23 species representing 17 genera were tested using real-time (rt)PCR and multi-locus sequence typing (MLST). Of the 1616 samples 251 (15.5%) were positive in an initial rtPCR. In 16 of the 23 investigated animal species rickettsial DNA was detected with an average prevalence of 15.7%. We herein describe for the first time four Rickettsia (R.) species known to be pathogenic for humans in rodents from South Africa, R. conorii, R. massiliae, R. felis and R. helvetica. In addition, by MLST and subsequent phylogenetic analyses so far undescribed Rickettsia species, Candidatus Rickettsia africaustralis, Candidatus Rickettsia rhabdomydis, and Candidatus Rickettsia muridii were confirmed. Further four new genotypes, genotype Rickettsia hofmannii, genotype Rickettsia stutterheimensis, genotype Rickettsia hogsbackensis and genotype Rickettsia kaalplaasensis, respectively, are described. The data indicate a surprisingly high diversity of Rickettsia in small mammals in South Africa and might indicate their possible role as reservoirs for Rickettsia. Ecological questions concerning their natural hosts such as small mammals, but also the role of livestock or pet animals, require further investigation. Particularly, data on the relevance of these rickettsiae for diseases in humans are of further interest.

State of the art of diagnosis of rickettsial diseases: the use of blood specimens for diagnosis of scrub typhus, spotted fever group rickettsiosis, and murine typhus

PURPOSE OF REVIEW

With improved malaria control, acute undifferentiated febrile illness studies in tropical regions reveal a startling proportion of rickettsial illnesses, especially scrub typhus, murine typhus, and spotted fever group rickettsioses. Laboratory diagnosis of these infections evolved little over the past 40 years, but combinations of technologies like PCR and loop-mediated isothermal amplification, with refined rapid diagnostic tests and/or ELISA, are promising for guidance for early antirickettsial treatment.

RECENT FINDINGS

The long-term reliance on serological tests - useful only late in rickettsial infections - has led to underdiagnosis, inappropriate therapies, and undocumented morbidity and mortality. Recent approaches integrate nucleic acid amplification and recombinant protein-based serological tests for diagnosing scrub typhus. Optimized using Bayesian latent class analyses, this strategy increases diagnostic confidence and enables early accurate diagnosis and treatment - a model to follow for lagging progress in murine typhus and spotted fever.

SUMMARY

A laboratory diagnostic paradigm shift in rickettsial infections is evolving, with replacement of indirect immunofluorescence assay by the more objective ELISA coupled with nucleic acid amplification assays to expand the diagnostic window toward early infection intervals. This approach supports targeted antirickettsial therapy, reduces morbidity and mortality, and provides a robust evidence base for further development of diagnostics and vaccines.

Reducing Uncertainty for Acute Febrile Illness in Resource-Limited Settings: The Current Diagnostic Landscape

AbstractDiagnosing the cause of acute febrile illness in resource-limited settings is important-to give the correct antimicrobials to patients who need them, to prevent unnecessary antimicrobial use, to detect emerging infectious diseases early, and to guide vaccine deployment. A variety of approaches are yielding more rapid and accurate tests that can detect more pathogens in a wider variety of settings. After decades of slow progress in diagnostics for acute febrile illness in resource-limited settings, a wave of converging advancements will enable clinicians in resource-limited settings to reduce uncertainty for the diagnosis of acute febrile illness.

Occurrence of <i>Coxiella burnetii</i>, <i>Ehrlichia canis</i>, <i>Rickettsia</i> species and <i>Anaplasma phagocytophilum</i>-like bacterium in ticks collected from dogs and cats in South Africa

Ticks are major vectors of arthropod-borne infections and transmit a wide variety of zoonotic pathogens. This study was conducted mainly to determine the occurrence of canine tick-borne bacterial and rickettsial pathogens especially those with zoonotic potential. We examined 276 Rhipicephalus sanguineus, 38 Haemaphysalis elliptica and 4 Amblyomma hebraeum ticks from 90 dogs and 4 cats from the Free State, KwaZulu-Natal, North West and Mpumalanga provinces. DNA of Coxiella burnetii (41%), Ehrlichia or Anaplasma (18%), Rickettsia spp. (37%), Anaplasma phagocytophilum-like bacterium (18%) and Ehrlichia canis (19%) was detected by polymerase chain reaction (PCR) from a total of 147 pooled DNA samples. All samples were negative for the presence of Borrelia burgdorferi DNA. Ehrlichia canis was detected in samples from all the provinces except the North West; A. phagocytophilum was absent in KwaZulu-Natal samples, whereas Rickettsia species and C. burnetii were detected in all sampled provinces. The PCR-positive samples were confirmed by direct sequencing of the product. Data from this study calls for a joint effort by both veterinary and medical sectors to conduct epidemiological studies of the zoonotic pathogens in both animals and humans.

Impact of introduction of rapid diagnostic tests for malaria on antibiotic prescribing: analysis of observational and randomised studies in public and private healthcare settings

Objectives To examine the impact of use of rapid diagnostic tests for malaria on prescribing of antimicrobials, specifically antibiotics, for acute febrile illness in Africa and Asia.Design Analysisof nine preselected linked and codesigned observational and randomised studies (eight cluster or individually randomised trials and one observational study).Setting Public and private healthcare settings, 2007-13, in Afghanistan, Cameroon, Ghana, Nigeria, Tanzania, and Uganda.Participants 522 480 children and adults with acute febrile illness.Interventions Rapid diagnostic tests for malaria.Main outcome measures Proportions of patients for whom an antibiotic was prescribed in trial groups who had undergone rapid diagnostic testing compared with controls and in patients with negative test results compared with patients with positive results. A secondary aim compared classes of antibiotics prescribed in different settings.Results Antibiotics were prescribed to 127 052/238 797 (53%) patients in control groups and 167 714/283 683 (59%) patients in intervention groups. Antibiotics were prescribed to 40% (35 505/89 719) of patients with a positive test result for malaria and to 69% (39 400/57 080) of those with a negative result. All but one study showed a trend toward more antibiotic prescribing in groups who underwent rapid diagnostic tests. Random effects meta-analysis of the trials showed that the overall risk of antibiotic prescription was 21% higher (95% confidence interval 7% to 36%) in intervention settings. In most intervention settings, patients with negative test results received more antibiotic prescriptions than patients with positive results for all the most commonly used classes: penicillins, trimethoprim-sulfamethoxazole (one exception), tetracyclines, and metronidazole.Conclusions Introduction of rapid diagnostic tests for malaria to reduce unnecessary use of antimalarials-a beneficial public health outcome-could drive up untargeted use of antibiotics. That 69% of patients were prescribed antibiotics when test results were negative probably represents overprescription.This included antibiotics from several classes, including those like metronidazole that are seldom appropriate for febrile illness, across varied clinical, health system, and epidemiological settings. It is often assumed that better disease specific diagnostics will reduce antimicrobial overuse, but they might simply shift it from one antimicrobial class to another. Current global implementation of malaria testing might increase untargeted antibiotic use and must be examined.

Coxiella burnetii (Q fever) prevalence in associated populations of humans and small ruminants in The Gambia

OBJECTIVES

To simultaneously estimate the prevalence of antibodies against Coxiella burnetii (Q fever) among adults and small ruminants, and C. burnetii shedding prevalence among small ruminants in households in the Kiang West district of The Gambia, and to assess associated risk factors.

METHODS

Sera of 599 adults and 615 small ruminants from 125 compounds within 12 villages were tested for antibodies against C. burnetii using ELISA. Vaginal swabs and milk samples of 155 small ruminants were tested using PCR to investigate shedding of C. burnetii.

RESULTS

A total of 3.8-9.7% of adults, depending on ELISA test cut-off, and 24.9% of small ruminants in Kiang West were seropositive. Having at least one seropositive animal in one's compound was a risk factor for human seropositivity (OR: 3.35, 95% CI: 1.09-14.44). A grazing area within a village was a risk factor for seropositivity in small ruminants (OR: 2.07, 95% CI: 1.26-3.50); others were having lambed (OR: 2.75, 95% CI: 1.37-5.76) and older age of the animals (OR: 2.75, 95% CI: 1.37-5.76 for 1-3 years and OR 5.84, 95% CI: 3.10-11.64 for >3 years); 57.4% of sampled small ruminants were shedding C. burnetii.

CONCLUSION

Coxiella burnetii infection is endemic among both humans and small ruminants in this area of The Gambia. Human and animal exposure to C. burnetii were related at compound level. Further research into the clinical relevance of C. burnetii infection in West Africa is needed.

From Q Fever to Coxiella burnetii Infection: a Paradigm Change

Coxiella burnetii is the agent of Q fever, or "query fever," a zoonosis first described in Australia in 1937. Since this first description, knowledge about this pathogen and its associated infections has increased dramatically. We review here all the progress made over the last 20 years on this topic. C. burnetii is classically a strict intracellular, Gram-negative bacterium. However, a major step in the characterization of this pathogen was achieved by the establishment of its axenic culture. C. burnetii infects a wide range of animals, from arthropods to humans. The genetic determinants of virulence are now better known, thanks to the achievement of determining the genome sequences of several strains of this species and comparative genomic analyses. Q fever can be found worldwide, but the epidemiological features of this disease vary according to the geographic area considered, including situations where it is endemic or hyperendemic, and the occurrence of large epidemic outbreaks. In recent years, a major breakthrough in the understanding of the natural history of human infection with C. burnetii was the breaking of the old dichotomy between "acute" and "chronic" Q fever. The clinical presentation of C. burnetii infection depends on both the virulence of the infecting C. burnetii strain and specific risks factors in the infected patient. Moreover, no persistent infection can exist without a focus of infection. This paradigm change should allow better diagnosis and management of primary infection and long-term complications in patients with C. burnetii infection.