Little is known about the extent and serotypes of dengue viruses circulating in Africa. We evaluated the presence of dengue viremia during 4 years of surveillance (2014–2017) among children with febrile illness in Kenya. Acutely ill febrile children were recruited from 4 clinical sites in western and coastal Kenya, and 1,022 participant samples were tested by using a highly sensitive real-time reverse transcription PCR. A complete case analysis with genomic sequencing and phylogenetic analyses was conducted to characterize the presence of dengue viremia among participants during 2014–2017. Dengue viremia was detected in 41.9% (361/862) of outpatient children who had undifferentiated febrile illness in Kenya. Of children with confirmed dengue viremia, 51.5% (150/291) had malaria parasitemia. All 4 dengue virus serotypes were detected, and phylogenetic analyses showed several viruses from novel lineages. Our results suggests high levels of dengue virus infection among children with undifferentiated febrile illness in Kenya.

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Modelling of emerging vector borne diseases serves as an important complement to clinical studies of modern zoonoses. This article presents an archaeo‐historic epidemiological modelling study of Rift Valley fever (RVF), using data‐driven neural network technology. RVF affects both human and animal populations, can rapidly decimate herds causing catastrophic economic hardship, and is identified as a Category A biodefense pathogen by the US Center for Disease Control. Despite recent origins circa the early 1900s, little is known about the circumstances of its inception nor the relationships between factors that affect transmission. This evidence could be vital as the disease continues to expand from its epicentre in Kenya to other parts of Africa and the Arabian Peninsula. RVF is a relevant case for archaeological/palaeopathological investigations of disease as it intersects between numerous human, animal, spatial, temporal, and sociopolitical dimensions. By integrating landscape archaeology, historical evidence, and climatic data, with evidence of human behaviour gathered through ethnoarchaeological study, this article presents an applied framework for human–animal palaeopathology. This framework aligns with the One Health approach that observes disease to be intrinsically tied to ecological and societal factors. We provide a useable alternative way of thinking about disease modelling in the present and the past, ultimately seeking to support efforts to accurately predict future impacts. Tapping into longitudinal evidence from the last 50–300 years offers a powerful way to respond to the threat zoonoses will pose to human populations around the world as the climate warms.

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Objective To evaluate pregnancy and neonatal outcomes, disease severity, and mother‐to‐child transmission of pregnant women with Chikungunya infection (CHIKV). Design Retrospective observational study. Setting Grenada. Population Women who gave birth during a Chikungunya outbreak between January 2014 and September 2015 were eligible. Methods This descriptive study investigated 731 mother‐infant pairs who gave birth during a CHIKV outbreak. Women and infants underwent serological testing for CHIKV by ELISA. Main outcome measures Primary outcomes: composite pregnancy complication (abruption, vaginal bleeding, preterm labour/cervical incompetence, cesarean delivery for fetal distress/abruption/placental abnormality or delivery for fetal distress) and composite neonatal morbidity. Results Of 416 mother‐infant pairs, 150 (36%) had CHIKV during pregnancy, 135 (33%) had never had CHIKV, and 131 (31%) had CHIKV outside of pregnancy. Mean duration of joint pain was shorter among women infected during pregnancy (μ = 898 days, σ = 277 days) compared with infections outside of pregnancy (μ = 1064 days, σ = 244 days) (P < 0.0001). Rates of pregnancy complications (RR = 0.76, P = 0.599), intrapartum complications (RR = 1.50, P = 0.633), and neonatal outcomes were otherwise similar. Possible mother‐to‐child transmission occurred in two (1.3%) mother‐infant pairs and two of eight intrapartum infections (25%). Conclusion CHIKV infection during pregnancy may be protective against long‐term joint pain sequelae that are often associated with acute CHIKV infection. Infection during pregnancy did not appear to pose a risk for pregnancy complications or neonatal health, but maternal infection just prior to delivery might have increased risk of mother‐to‐child transmission of CHIKV. Tweetable abstract Chikungunya infection did not increase risk of pregnancy complications or adverse neonatal outcomes, unless infection was just prior to delivery.

Rift Valley fever virus (RVFV) is an important animal and human threat and leads to longstanding morbidity and mortality in susceptible hosts. Since no therapies currently exist to treat Rift Valley fever, it remains a public and animal health priority to develop safe, effective RVFV vaccines (whether for animals, humans, or both) that provide long-term protective immunity. In the evaluated article, Bhardwaj and colleagues describe the creation and testing of two successful vaccine strategies against RVFV, a DNA plasmid vaccine expressing Gn coupled to C3d, and an alpha-virus replicon vaccine expressing Gn protein. Both vaccines elicited strong neutralizing antibody responses, prevented morbidity and mortality in RVFV-challenged mice, and enabled protection of naive mice via passive antibody transfer from vaccinated mice. Both DNA and replicon RVFV vaccines have previously been shown to protect against RVFV challenge, but these results allow for direct comparison of the two methods and evaluation of a combined primeboost method. The results also highlight the specific humoral and cell-mediated immune responses to vaccination. Keywords Rift Valley Fever; vaccine Summary of methodsIn their study, Bhardwaj and colleagues performed experiments to directly compare DNA vaccines and alphavirus vaccines expressing Rift Valley Fever virus (RVFV) Gn, evaluate the efficacy of these DNA vaccines against Rift Valley Fever (RVF) in a mouse model, determine whether a prime-boost strategy enhances efficacy, and assess the nature of the immune response to vaccination [1]. RVFV is a member of the Phlebovirus genus, one of the five genera in the family Bunyaviridae [101]. RVFV, similar to other Bunyaviruses, has a single-stranded, tripartite-negative or ambisense-coded RNA genome, composed of the L, M and S segments encoding four structural proteins, viral polymerase (L segment), glycoproteins (M segment) and nucleocapsid protein N (S segment) [2]. RVFV is a highpriority pathogen because of its ability to cause blindness, encephalitis and life-threatening hemorrhagic fever in humans [3,102], its potential for severe economic harm to livestock [101], and its potential for nonvector aerosol spread during epizootics and epidemics [4,5].

This paper describes the spatial and temporal distribution of cases, demographic characteristics of patients, and clinical manifestations of Zika virus (ZIKV) during the 2016 outbreak in Grenada. The first reported case was recorded in St. Andrew Parish in April, and the last reported case was seen in November, with peak transmission occurring in the last week of June, based on test results. Data were collected from a total of 514 patients, of whom 207 (40%) tested positive for ZIKV. No evidence was found that testing positive for ZIKV infection was related to age, gender, or pregnancy status. Clinical presentation with rash (OR = 2.4, 95% CI = 1.5 to 3.7) or with lymphadenopathy (OR = 1.7, 95% CI = 1.0 to 2.9) were the only reported symptoms consistent with testing positive for ZIKV infection. During the Zika outbreak, the infection rate was 20 clinical cases per 10,000 in the population compared to 41 cases per 10,000 during the chikungunya outbreak in Grenada in 2014 and 17 cases per 10,000 during the dengue outbreak in 2001-2002. Even though the country has employed vector control programs, with no apparent decrease in infection rates, it appears that new abatement approaches are needed to minimize morbidity in future arbovirus outbreaks.

The current ZIKV outbreak has illustrated the emergent capabilities of mosquito-borne viruses and the teratogenic nature of ZIKV. Causality and risk factors associated with severe manifestations, as well as chronic sequelae, have yet to be determined. Extensive research is required to understand the molecular mechanisms of infection, develop improved assays for differential diagnosis, and improve overall knowledge of the spectrum of ZIKV disease in order to develop modes of prevention and treatment.