Similar virus spectra and seasonality in paediatric patients with acute respiratory disease, Ghana and Germany

Abstract

Epidemiological differences between tropical and temperate regions regarding viruses causing acute respiratory infection are poorly understood. This is in part because methodological differences limit the comparability of data from these two regions. Using identical molecular detection methods, we tested 1174 Ghanaian and 539 German children with acute respiratory infections sampled over 12 months for the 15 most common respiratory viruses by PCR. A total 43.2% of the Ghanaian and 56.6% of the German children tested positive for at least one respiratory virus. The pneumoviruses respiratory syncytial virus and human metapneumovirus were most frequently detected, in 13.1% and 25.1% within the Ghanaian and German children, respectively. At both study sites, pneumoviruses were more often observed at younger ages (p <0.001). In the Ghanaian rainy season, enveloped viruses were detected twice as often as non-enveloped viruses (prevalence rate ratio (PR) 2.0, 95% CI 1.7-2.4). In contrast, non-enveloped viruses were more frequent during the Ghanaian dry season (PR 0.6, 95% CI 0.4-0.8). In Germany, enveloped viruses were also more frequently detected during the relatively colder winter season (PR 1.6, 95% CI 1.2-2.1) and non-enveloped viruses during summer (PR 0.7, 95% CI 0.5-0.9). Despite a distance of about 5000 km and a difference of 44° latitude separating Germany and Ghana, virus spectra, age associations and seasonal fluctuation showed similarities between sites. Neither respiratory viruses overall, nor environmentally stable (non-enveloped) viruses in particular were more frequent in tropical Ghana. The standardization of our sampling and laboratory testing revealed similarities in acute respiratory infection virus patterns in tropical and temperate climates.

Keywords: Epidemiology; Germany; Ghana; PCR; infant; respiratory tract infections; viruses.

Fig. 1

Virus seasonality. Seasonality of enveloped viruses (a) and non-enveloped viruses (b) in Kumasi, Ghana and of enveloped viruses (c) and non-enveloped viruses (d) in Bonn, Germany. Blue-shaded months represent winter in Germany and rainy season in Ghana, the black line indicates the aggregate number of collected samples per month. In (c) and (d), primary and secondary y-scales differ to ensure visibility of individual viruses showing low detection rates.

Fig. 2

Viral co-infections. (a) Percentage of multiple infections at the two study sites. The total number of patients testing positive for any virus under study is indicated below sites. (b) Co-infections of individual viruses in Kumasi, Ghana and Bonn, Germany. The pie chart shows percentage of cases with a single infection of the respective pathogen (slice a), the share of multiple infections (slice b) and the co-infecting viruses identified by individual colours (slice c). The total number of individual virus detections is given below each pie chart per site.