Almost all hospitals are equipped with air-conditioning systems to provide a comfortable environment for patients and staff. However, the accumulation of dust and moisture within these systems increases the risk of transmission of microbes and have on occasion been associated with outbreaks of infection. Nevertheless, the impact of air-conditioning on the transmission of microorganisms leading to infection remains largely uncertain. We conducted a scoping review to screen systematically the evidence for such an association in the face of the coronavirus disease 2019 epidemic. PubMed, Embase and Web of Science databases were explored for relevant studies addressing microbial contamination of the air, their transmission and association with infectious diseases. The review process yielded 21 publications, 17 of which were cross-sectional studies, three were cohort studies and one case−control study. Our analysis showed that, compared with naturally ventilated areas, microbial loads were significantly lower in air-conditioned areas, but the incidence of infections increased if not properly managed. The use of high-efficiency particulate air (HEPA) filtration not only decreased transmission of airborne bioaerosols and various microorganisms, but also reduced the risk of infections. By contrast, contaminated air-conditioning systems in hospital rooms were associated with a higher risk of patient infection. Cleaning and maintenance of such systems to recommended standards should be performed regularly and where appropriate, the installation of HEPA filters can effectively mitigate microbial contamination in the public areas of hospitals.

Several species of Chilo occur on sugar-cane, out of which five have major pest status. Infestation by these pests causes losses in cane yield and sugar recovery. There are constraints involved in the use of cultural, mechanical and chemical control measures on a large scale, but the nature of the crop facilitates adoption of biological control. Many species of natural enemies occur in the sugar-cane agro-ecosystem, which is relatively less disturbed. They play a significant role in maintaining the pest populations at reasonably low level.

In biological control, the egg parasite, Trichogramma spp., has been widely used with varying results. Among the larval parasites, Apanteles flavipes (Cameron) and Sturmiopsis inferens Townsend have been used on a limited scale and need further testing in other countries. The exotic tachinids introduced, failed to establish against Chilo spp. Not much work has been done on the predators, though the native predators play a significant role in reducing the pest densities. Among the entomopathogens, granulosis virus infecting Chilo infuscatellus Snellen has shown promise in the control of this pest and needs further evaluation in other agro-climatic regions. Future thrust for biological control of Chilo spp., in sugar-cane has also been indicated.

Field surveys along the Lake Basin and the Coastal regions of Kenya were carried out to assess the natural incidence of pathogenic microorganisms associated with the legume pod-borer, Maruca testulalis Geyer on the cowpea crop. A regular sampling regime was maintained on plots planted with four varieties of cowpea: T VX 66–2H, Vita 3 (TVU 1190), Ex-Luanda and Nyar-Milambo. Larvae of M. testulalis were recovered from the flowers and pods of the crop, and subjected to routine laboratory disease diagnosis including: tissue examination, culture incubation, microscopy and pathogen identification. The main groups of pathogenic microorganisms found to act as natural mortality factors to M. testulalis larvae include: protozoa, bacteria, fungi and a virus. A higher level of disease incidence and diversity on M. testulalis larvae occurred in the lake basin region of Kenya than the coastal part.