The Relationship between Pneumocystis Infection in Animal and Human Hosts, and Climatological and Environmental Air Pollution Factors: A Systematic Review

Abstract

Background: Over the past decade, there has been rising interest in the interaction of Pneumocystis with the environment. This interest has arisen in part from the demonstration that environmental factors have important effects on the viability and transmission of microbes, including Pneumocystis. Environmental factors include climatological factors such as temperature, humidity, and precipitation, and air pollution factors including carbon monoxide, nitrogen dioxide, sulfur dioxide, and particulate matter. Methods: We undertook a systematic review in order to identify environmental factors associated with Pneumocystis infection or PCP, and their effects on human and animal hosts. Results: The systematic review found evidence of associations between Pneumocystis infection in animal and human hosts, and climatological and air pollution factors. Data from human studies infers that rather than a seasonal association, presentation with PCP appears to be highest when the average temperature is between 10 and 20°C. There was evidence of an association with hospitalization with PCP and ambient air pollution factors, as well as evidence of an effect of air pollution on both systemic and bronchoscopic lavage fluid humoral responses to Pneumocystis. Interpretation of human studies was confounded by possible genetically-determined predisposition to, or protection from infection. Conclusions: This systematic review provides evidence of associations between Pneumocystis infection in both animal and human hosts, and climatological and environmental air pollution factors. This information may lead to an improved understanding of the conditions involved in transmission of Pneumocystis in both animal and human hosts. Such knowledge is critical to efforts aimed at prevention.

Pneumocystis primary infection in non-immunosuppressed infants in Lima, Peru

“…Be that as it may, the higher rate of P. jirovecii detection in infants was effectively observed in the cooler months of the spring and the winter in Lima when the average temperature was around 21°C. This may be consistent with reports described elsewhere showing an association of PCP occurrence in immunosuppressed patients with average temperatures from 10°C to 20°C rather than with the seasons themselves [30]. In Chile, the highest rate of P. jirovecii detection in autopsied infants was in winter, when the average temperatures were 16°C-18°C whereas the lowest rate was in the fall when the average temperatures were 20°C-28°C [31].…”

Pneumocystis spp. in Pigs: A Longitudinal Quantitative Study and Co-Infection Assessment in Austrian Farms

“…Its presence has been successively reported in studies conducted on swine farms or abattoirs in Austria, Denmark, Portugal, Brazil, Japan, and South Korea [13][14][15][16][17][18][19][20]. Its prevalence ranges between 7 and 51% [15,17,21], with variation according to geographic distribution, climate, and farm management [22]. This variation was also observed in our annual routine diagnostics data (Blasi, unpublished data).…”

Influence of Climate on Pneumocystosis Cases in the Eastern Brazilian Amazon

“…A positive correlation has been observed between the incidence of pneumocystosis and climatic factors such as average temperature [12], and climatological and environmental air pollution factors [13,14]. In San Francisco (USA), changes in climatic factors and high levels of the polluting constituents in ambient air, temperature, and SO 2 were observed immediately (0-3 days) before pneumocystosis-related admission among HIV-positive patients living in the city [13].…”