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A Decrease in Temperature and Humidity Precedes Human Rhinovirus Infections in a Cold Climate

View Article: PubMed Central - PubMed

ABSTRACT

Both temperature and humidity may independently or jointly contribute to the risk of human rhinovirus (HRV) infections, either through altered survival and spread of viruses in the environment or due to changes in host susceptibility. This study examined the relationship between short-term variations in temperature and humidity and the risk of HRV infections in a subarctic climate. We conducted a case-crossover study among conscripts (n = 892) seeking medical attention due to respiratory symptoms during their military training and identified 147 HRV cases by real-time PCR. An average temperature, a decline in daily ambient temperature and absolute humidity (AH) during the three preceding days of the onset (hazard period) and two reference periods (a week prior and after the onset) were obtained. The average daily temperature preceding HRV infections was −9.9 ± 4.9 °C and the average AH was 2.2 ± 0.9 g/m3. An average (odds ratios (OR) 1.07 (95% confidence interval (CI) 1.00–1.15)) and maximal (OR 1.08 (1.01–1.17)) change in temperature increased the risk of HRV infections by 8% per 1 °C decrease. An average (OR 1.20 (CI 1.03–1.40)) and maximal decrease (OR 1.13 (CI 0.96–1.34)) in AH increased the risk of HRV infection by 13% and 20% per 0.5 g/m3 decrease. A higher average temperature during the three preceding days was positively associated with HRV infections (OR 1.07 (CI 1.00–1.15)). A decrease rather than low temperature and humidity per se during the preceding few days increases the risk of HRV infections in a cold climate. The information is applicable to populations residing in cold climates for appropriate personal protection and prevention of adverse health effects.

No MeSH data available.


Related in: MedlinePlus

Incidence of rhinovirus infections, average temperature (°C; black solid line) and absolute humidity (AH) (g/m3; grey dotted line) during the study period.
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viruses-08-00244-f001: Incidence of rhinovirus infections, average temperature (°C; black solid line) and absolute humidity (AH) (g/m3; grey dotted line) during the study period.

Mentions: Out of 386 sputum specimens, 147 (37.8%) were analysed by real-time RT-PCR [28] and found positive for HRV. A majority of the episodes were detected during the winter season and occurred as follows: 13 in November 2004, 13 in December 2004, 13 in January 2005, 29 in February 2005, 33 in March 2005, 16 in April 2005, 5 in May 2005, and 7 in June 2005. The remaining episodes were scattered over the rest of the winter season. The temperature ranged from −22.8 °C to 22.0 °C (± 10.1) and AH from 0.8 g/m3 to 14.3 g/m3 (± 3.2) during the follow-up (Figure 1). We observed that 74% of the infection episodes occurred when temperatures were ≤0 °C (109 of 147) and 26% when temperatures were above 0 °C (38 of 147). Of those conscripts infected by HRV who were engaged in outdoor training, 89% (76 of 85) reported being engaged in physical exercise, 73% (62 of 85) felt symptoms of freezing and 36% (31 of 85) reported wetting of socks or gloves during the three days prior to seeking medical consultation.


A Decrease in Temperature and Humidity Precedes Human Rhinovirus Infections in a Cold Climate
Incidence of rhinovirus infections, average temperature (°C; black solid line) and absolute humidity (AH) (g/m3; grey dotted line) during the study period.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5035958&req=5

viruses-08-00244-f001: Incidence of rhinovirus infections, average temperature (°C; black solid line) and absolute humidity (AH) (g/m3; grey dotted line) during the study period.
Mentions: Out of 386 sputum specimens, 147 (37.8%) were analysed by real-time RT-PCR [28] and found positive for HRV. A majority of the episodes were detected during the winter season and occurred as follows: 13 in November 2004, 13 in December 2004, 13 in January 2005, 29 in February 2005, 33 in March 2005, 16 in April 2005, 5 in May 2005, and 7 in June 2005. The remaining episodes were scattered over the rest of the winter season. The temperature ranged from −22.8 °C to 22.0 °C (± 10.1) and AH from 0.8 g/m3 to 14.3 g/m3 (± 3.2) during the follow-up (Figure 1). We observed that 74% of the infection episodes occurred when temperatures were ≤0 °C (109 of 147) and 26% when temperatures were above 0 °C (38 of 147). Of those conscripts infected by HRV who were engaged in outdoor training, 89% (76 of 85) reported being engaged in physical exercise, 73% (62 of 85) felt symptoms of freezing and 36% (31 of 85) reported wetting of socks or gloves during the three days prior to seeking medical consultation.

View Article: PubMed Central - PubMed

ABSTRACT

Both temperature and humidity may independently or jointly contribute to the risk of human rhinovirus (HRV) infections, either through altered survival and spread of viruses in the environment or due to changes in host susceptibility. This study examined the relationship between short-term variations in temperature and humidity and the risk of HRV infections in a subarctic climate. We conducted a case-crossover study among conscripts (n = 892) seeking medical attention due to respiratory symptoms during their military training and identified 147 HRV cases by real-time PCR. An average temperature, a decline in daily ambient temperature and absolute humidity (AH) during the three preceding days of the onset (hazard period) and two reference periods (a week prior and after the onset) were obtained. The average daily temperature preceding HRV infections was −9.9 ± 4.9 °C and the average AH was 2.2 ± 0.9 g/m3. An average (odds ratios (OR) 1.07 (95% confidence interval (CI) 1.00–1.15)) and maximal (OR 1.08 (1.01–1.17)) change in temperature increased the risk of HRV infections by 8% per 1 °C decrease. An average (OR 1.20 (CI 1.03–1.40)) and maximal decrease (OR 1.13 (CI 0.96–1.34)) in AH increased the risk of HRV infection by 13% and 20% per 0.5 g/m3 decrease. A higher average temperature during the three preceding days was positively associated with HRV infections (OR 1.07 (CI 1.00–1.15)). A decrease rather than low temperature and humidity per se during the preceding few days increases the risk of HRV infections in a cold climate. The information is applicable to populations residing in cold climates for appropriate personal protection and prevention of adverse health effects.

No MeSH data available.


Related in: MedlinePlus