BackgroundHuman coronavirus NL63 (HCoV-NL63) is a globally endemic pathogen causing mild and severe respiratory tract infections with reinfections occurring repeatedly throughout a lifetime.MethodsNasal samples were collected in coastal Kenya through community-based and hospital-based surveillance. HCoV-NL63 was detected with multiplex real-time reverse transcription PCR, and positive samples were targeted for nucleotide sequencing of the spike (S) protein. Additionally, paired samples from 25 individuals with evidence of repeat HCoV-NL63 infection were selected for whole-genome virus sequencing.ResultsHCoV-NL63 was detected in 1.3% (75/5573) of child pneumonia admissions. Two HCoV-NL63 genotypes circulated in Kilifi between 2008 and 2014. Full genome sequences formed a monophyletic clade closely related to contemporary HCoV-NL63 from other global locations. An unexpected pattern of repeat infections was observed with some individuals showing higher viral titers during their second infection. Similar patterns for 2 other endemic coronaviruses, HCoV-229E and HCoV-OC43, were observed. Repeat infections by HCoV-NL63 were not accompanied by detectable genotype switching.ConclusionsIn this coastal Kenya setting, HCoV-NL63 exhibited low prevalence in hospital pediatric pneumonia admissions. Clade persistence with low genetic diversity suggest limited immune selection, and absence of detectable clade switching in reinfections indicates initial exposure was insufficient to elicit a protective immune response.

Background: Endemic and seasonally recurring respiratory viruses are a major cause of disease and death globally. The burden is particularly severe in developing countries. Improved understanding of the source of infection, pathways of spread and persistence in communities would be of benefit in devising intervention strategies. Methods: We report epidemiological data obtained through surveillance of respiratory viruses at nine outpatient health facilities within the Kilifi Health and Demographic Surveillance System, Kilifi County, coastal Kenya, between January and December 2016. Nasopharyngeal swabs were collected from individuals of all ages presenting with acute respiratory infection (ARI) symptoms (up to 15 swabs per week per facility) and screened for 15 respiratory viruses using real-time PCR. Paediatric inpatient surveillance at Kilifi County Hospital for respiratory viruses provided comparative data. Results: Over the year, 5,647 participants were sampled, of which 3,029 (53.7%) were aged <5 years. At least one target respiratory virus was detected in 2,380 (42.2%) of the samples; the most common being rhinovirus 18.6% (1,050), influenza virus 6.9% (390), coronavirus 6.8% (387), parainfluenza virus 6.6% (371), respiratory syncytial virus (RSV) 3.9% (219) and adenovirus 2.7% (155). Virus detections were higher among <5-year-olds compared to older children and adults (50.3% vs 32.7%, respectively; χ 2(1) =177.3, P=0.0001). Frequency of viruses did not differ significantly by facility (χ 2(8) =13.38, P=0.072). However, prevalence was significantly higher among inpatients than outpatients in <5-year-olds for RSV (22.1% vs 6.0%; χ 2(1) = 159.4, P=0.0001), and adenovirus (12.4% vs 4.4%, χ 2(1) =56.6, P=0.0001). Conclusions: Respiratory virus infections are common amongst ARI outpatients in this coastal Kenya setting, particularly in young children. Rhinovirus predominance warrants further studies on the health and socio-economic implications. RSV and adenovirus were more commonly associated with severe disease. Further analysis will explore epidemiological transmission patterns with the addition of virus sequence data.

In February 2012, the novel respiratory syncytial virus (RSV) group A, genotype ON1, was detected in Kilifi County, coastal Kenya. ON1 is characterized by a 72-nt duplication within the highly variable G gene (encoding the immunogenic attachment surface protein). Cases were diagnosed through surveillance of pneumonia in children at the county hospital. Analysis of epidemiologic, clinical, and sequence data of RSV-A viruses detected over 5 RSV seasons (2010/2011 to 2014/2015) indicated the following: 1) replacement of previously circulating genotype GA2 ON1, 2) an abrupt expansion in the number of ON1 variants detected in the 2014/2015 epidemic, 3) recently accumulation of amino acid substitutions within the ON1 duplicated sequence, and 4) no clear evidence of altered pathogenicity relative to GA2. The study demonstrates the public health importance of molecular surveillance in defining the spread, clinical effects, and evolution of novel respiratory virus variants.

We determined the change in seroprevalence of enterovirus D68 (EV-D68) in the United Kingdom in age-stratified cohorts from 2006 to 2016, the period during which EV-D68 emerged as a cause of severe respiratory disease occasionally leading to paralysis. Infections were acquired primarily in infants and young children, and incidence was markedly higher in 2016.

Transforming growth factor beta (TGF-␤) is a pleiotropic cytokine known to regulate cell growth, differentiation, and motility and is a potent modulator of immune function. TGF-␤ consequently plays a central role in carcinogenesis, and a dampened TGF-␤2 response by Theileria annulata-infected monocytes/macrophages underpins disease resistance to tropical theileriosis. Here, we show that concomitant with the loss of TGF-␤2 production, there is ablated expression of COX2 and EP4, which leads to a drop in cyclic AMP (cAMP) levels and, consequently, reduced activation of protein kinase A (PKA) and EPAC. This ablated phenotype can be rescued in attenuated macrophages by the addition of exogenous TGF-␤2, which reactivates the expression of COX2 and EP4 while repressing that of protein kinase inhibitor gamma (PKIG) to the levels in virulent macrophages. TGF-␤2 therefore promotes the adhesion and invasiveness of virulent macrophages by modulating COX2, EP4, and PKIG transcription to initiate a prostaglandin E 2 (PGE2)-driven autostimulatory loop that augments PKA and EPAC activities. A virulence phenotype stemming from the double activation of PKA and EPAC is the induction of a CREB-mediated transcriptional program and the upregulation of JAM-L-and integrin 4␣␤1-mediated adhesion of Theileria-infected macrophages.T heileria annulata is a tick-borne apicomplexan parasite and the causative agent of the cattle disease tropical theileriosis, which is of major economic importance in countries in Northern Africa and Asia. T. annulata transforms B cells and monocytes/macrophages, and infected leukocytes display many characteristics of cancer cells, such as heightened migratory and invasive capacities (1, 2). However, and importantly, the tumor-like phenotype is reversed upon drug-induced parasite death (3). Moreover, virulent macrophages can be attenuated by multiple in vitro passages, and upon attenuation, they lose both adhesion and invasiveness (4). The similarities in tumor hyperinvasiveness between Theileria-transformed leukocytes and human leukemias argue that studying Theileria-induced transformation can give insights into generally applicable mechanisms involved in tumor virulence.Transforming growth factor beta (TGF-␤) is a pleiotropic cytokine involved in numerous critical processes such as cell proliferation, differentiation, and survival or apoptosis. In normal cells and cells in early stages of cancer, TGF-␤ acts as a tumor suppressor and inhibits cell growth, while in late stages of cancer, it plays a contrasting role, acting as a tumor promoter enhancing metastasis and invasion. TGF-␤2 is strongly expressed in highly aggressive and malignant tumors (5). We have demonstrated that following infection, Theileria-transformed Holstein-Friesian (HF) (Bos taurus) macrophages produce more TGF-␤2 than do infected Sahiwal (Bos indicus) macrophages, and augmented TGF-␤2 output underpins the greater invasive capacity of infected HF macrophages. Moreover, attenuated Ode HF macrophages used as a live vaccine against tropical ...