Table 1. Seasonal drivers of human infectious diseases.

Drivers categorized as being related to (a) vector seasonality, (b) seasonality in nonhuman animal host (i.e., livestock, other domestic animals, or wildlife), (c) seasonal climate (e.g., temperature, precipitation, etc.), (d) seasonal nonclimatic abiotic environment (e.g., water salinity), (e) seasonal co-infection, (f) seasonal exposure and/or behavior and/or contact rate, (g) seasonal biotic environment (e.g., algal density in waterbodies).

Infection/disease	Type	Seasonal driver(s)	Description
African sleeping sickness	Chronic	a	Tsetse fly distribution changes seasonally; expanded range during rainy season [7]
Anthrax	Acute	b	Zoonotic disease with seasonality reported in wildlife and livestock; seasonality varies among location and species [8]
Avian influenza	Acute	b	Winter in both humans and poultry (in Asia) [9, 10]
Bacterial Pneumonia	Acute	c, d, and e	Peaks in midwinter (in the US); it is associated with influenza [11]
Brucellosis	Acute	b	Spring and summer in wildlife and livestock; the timing relates to the birthing season; peaks in the summer in humans [12]
Buruli ulcer	Chronic	c	Varies by location; some studies have not observed seasonality [13]
Chagas disease	Acute and chronic	a	Peaks in spring and summer in countries with distinct seasons [14]
Chickenpox	acute	f	Peak in spring in the Northern and Southern Hemisphere [15]
Chikungunya	Acute	a	Rainy season when vector density peaks. [16]
Cholera	Acute	c, d, and g	Seasonality is stronger in countries further from the equator; outbreaks generally occur in warm months [17]
Crimean-Congo hemorrhagic fever	Acute	a	Seropositivity in livestock correlates with seasonal changes in tick parasitism; human cases correlate with livestock seropositivity [18]
Cryptosporidium	Acute	c	Increased risk of cryptosporidium associated with high ambient temperature and high rainfall [19]
Cutaneous leishmaniasis	Acute and chronic	a and b	Strong seasonal variation with elevated incidence from October to March (in Tunisia). Seasonality may be due to climate effects on the vector: blood-feeding sand flies [20]
Dengue fever	Acute	a	Rainy season (in Thailand) [21]
Diphtheria	Acute	f	Spring and summer (in Portugal) [22]
Dracunculiasis	Chronic	c, d, f, and g	Dry season (in Nigeria) [23]
Ebola	Acute	b	In wildlife the peak is in the dry season (in Gabon) [24]
Echinococcosis	Chronic	b	Exposure to livestock carrying the infection is seasonal [25]
Escherichia coli (pathogenic)	Acute	b	Seasonal in cattle; cattle are a source for human infection [26]
Foodborne trematodiases	Chronic	f	Exposure is seasonal due to seasonal ingestion of infected snails [27]
Genital herpes	Chronic	f	Elevated incidence in spring/summer and lower in winter (in the US) [28]
Gonorrhea	Chronic	f	Peak cases in the summer and autumn (in the US) [28]

Since seasonal timing may differ among geographic areas, study location is indicated in parentheses.