Table 1.

Animal studies showing associations between detection of Pneumocystis spp and seasonal and environmental factors.

Study authors	Year	Species	Location	Methods	Main findings
Šebek & Rosický [8]	1967	Shrew species (Sorex araneus, Sorex alpinus, and Neomys fodiens)	Multiple rural locations, Czechoslovakia.	Grocott silver staining	Pneumocystis identified in 7/44 (16%) of shrews, only in Spring, and not in Autumn.
Poelma & Broekhuizen [9]	1972	Hare (Lepus europaeus)	Research Institute of Nature Management, Arnhem, Netherlands.	Grocott silver staining	Pneumocystis identified in 75/437 (17%) of hares, most commonly identified during the period September to December.
Shiota, Kurimoto & Yoshida [10]	1986	Wild mouse species (Apodemus speciosus, Apodemus argenteus, Microtus montebelli, Mus musculus)	6 localities, Japan.	Grocott silver staining	Pneumocystis detected in 11/142 (7.7%) of Apodemus speciosus; higher detection rate in Winter-Spring than in Summer-Autumn.
Laakkonen, et al [11]	1999	Field vole (Microtus agrestis) & Common shrew (Sorex araneus)	Rural Central (Luhanka) and Southern (Evo) Finland.	Grocott silver staining	Highest rates of Pneumocystis detection in both Microtus agrestis and Sorex araneus seen in November.
Demanche, et al [12]	2003	Crab-eating macaque (Macaca fascicularis)	Primatology Center, Strasburg, France.	PCR	Detection of Pneumocystis in 166/481 (34.5%) macaques: higher detection rate associated with mean precipitation rates.
Icenhour, et al [13]	2006	Brown Norway & Long Evans rats	Laboratory facility, Cincinnati, USA.	PCR	Higher relative humidity associated with predominance of P. carinii, higher temperatures associated with mixed infections of P. carinii and P. wakefieldiae and lower temperature associated with predominance of P. wakefieldiae.
Sanches, et al [14]	2007	Pigs	Slaughterhouses, in Rio Grande do Sul, and Mato Grosso, Brazil.	Grocott silver staining Immunohi sto- chemistry	Pneumocystis detected in 208/546 (36.9%) of pigs slaughtered in February-March (summer). Detection rate higher (39.9%) in slaughterhouse with a lower average temperature (Rio Grande do Sul: 23°C) than in Mato Grosso slaughterhouse (27°C).
Kim, et al [15]	2011	Pigs	Farms on Jeju Island, Korea.	Immunohi sto-chemistry	Pneumocystis detected in 39/172 (22.7%) of pigs. More commonly detected in cold season (December-March: temperature 8–9°C), than in hot season (June-September: temperature 21–23°C). Detection of Pneumocystis associated with PCV2 and PRRSV infection; in 32/139 (23%) virus positive, and in 4/28 (14%) of virus negative pigs.
Akbar, et al [16]	2012	Bats (New World and Old World microchiropters and Old World megachiropters)	New World (Mexico, Guyana, and Argentina wild bats and Old World (France) wild and captive bat colonies.	PCR	Pneumocystis identified in lungs of 71 of 216 (32.9%) of 19 bat species. More commonly detected in smaller, sedentary and crowded bat colonies. Also in colonies at <800m elevation. No association with geographical (cave) temperature or relative humidity.
Esgalhado, et al [17]	2013	Pigs	Slaughterhouses in the Lisbon and Tagus valley, Portugal.	PCR	Pneumocystis detected in 14/215 (7%) of pigs. Detection rates higher in pigs raised in Center and Algarve regions (10–13%), than in pigs from Lisbon and Alentejo regions (4–5%). No association with median temperature; association with extremely low and high precipitation rates. Detection more likely in semi-intensively farmed pigs (10%), than in intensively farmed pigs (5%)
Weissenbache r-Lang, et al [18]	2016	Pigs	Institute of Pathology and Forensic Veterinary Medicine, Vienna, Austria.	ISH/PCR	110 Pneumocystis positive pigs with pneumonia; many also had viral (PCV2, PRRSV, TTSuV1, TTSuV2), and/or bacterial (B. bronchiseptica, P. multocida, M. hyopneumoniae) infection. 79% of moderate and severe Pneumocystis seen in Winter-Spring (December-May).

Key: PCR = polymerase chain reaction; ISH = in situ hybridization; PCV2 = porcine circovirus type 2; PRRSV = porcine reproductive and respiratory syndrome virus; TTSuV1, TTSuV2 = torque teno sus virus type 1 and 2.