These studies use different models, time
stamps, and control for different covariants.
So they should be compared with caution.
The six studies summarized in the top half of the
figure used all cause diarrhea
or infectious gastroenteritis for their outcomes.
The three studies in the bottom half report results for rotavirus.
Since the six studies summarized in the top half
are not pathogen-specific the causes for diarrhea may include protozoa.
For example Giardia, Crytosporidium, or bacteria, for example, E
Coli, or Campylobacter, or viruses, for example Rotavirus and Norovirus.
The results for all cause diarrhea suggest a three to 11% increase
in cases with each one degree celsius increasing in mean ambient temperature.
However, one matter analysis by Lloyd and Co authors from 2007
did not find a significant relationship between temperature and diarrheal disease.
However, this study used large annual or multi annual study length time
steps instead of shorter weekly or monthly time steps like the individual studies.
and found rainfall to be significant.
Two of the rotovirus studies, both Gigiatahl and
leviatahl, found a negative correlation between temperature and rotovirus.
This corroborates the general findings that
rotovirus cases expand in colder months.
Likely because of greater time spent indoors.
With the hypothesis being that part of the transmission is through inhalation or air.