Intensity Of Disease Transmission Research Articles

The interaction of disease transmission, mortality, and economic output over the first 2 years of the COVID-19 pandemic.

The COVID-19 pandemic has caused over 7.02 million deaths as of January 2024 and profoundly affected most countries' Gross Domestic Product (GDP). Here, we study the interaction of SARS-CoV-2 transmission, mortality, and economic output between January 2020 and December 2022 across 25 European countries. We use a Bayesian mixed effects model with auto-regressive terms to estimate the temporal relationships between disease transmission, excess deaths, changes in economic output, transit mobility and non-pharmaceutical interventions (NPIs) across countries. Disease transmission intensity (logRt) decreases GDP and increases excess deaths, where the latter association is longer-lasting. Changes in GDP as well as prior week transmission intensity are both negatively associated with each other (-0.241, 95% CrI: -0.295 - -0.189). We find evidence of risk-averse behaviour, as changes in transit and prior week transmission intensity are negatively associated (-0.055, 95% CrI: -0.074 to -0.036). Our results highlight a complex cost-benefit trade-off from individual NPIs. For example, banning international travel is associated with both increases in GDP (0.014, 0.002-0.025) and decreases in excess deaths (-0.014, 95% CrI: -0.028 - -0.001). Country-specific random effects, such as the poverty rate, are positively associated with excess deaths while the UN government effectiveness index is negatively associated with excess deaths. The interplay between transmission intensity, excess deaths, population mobility and economic output is highly complex, and none of these factors can be considered in isolation. Our results reinforce the intuitive idea that significant economic activity arises from diverse person-to-person interactions. Our analysis quantifies and highlights that the impact of disease on a given country is complex and multifaceted. Long-term economic impairments are not fully captured by our model, as well as long-term disease effects (Long COVID).

Strategies and challenges in Kerala’s response to the initial phase of COVID-19 pandemic: a qualitative descriptive study

ObjectiveTo understand the structures and strategies that helped Kerala in fighting the COVID-19 pandemic, the challenges faced by the state and how it was tackled.DesignQualitative descriptive study using focus group...

The effects of climate change on avian migratory patterns and the dispersal of commercial poultry diseases in Canada - Part II

Climate change has already provoked a northward shift in the geographic range of many bird species, and current climate projections favour the modification of avian distributions and migratory routes. Given that wild birds are recognised as pathogen-dispersing agents, there is concern that changes in migrant ranges and movement patterns will increase the frequency of bird-borne pathogens reaching Northern areas, such as Canada. Furthermore, climate change will likely affect vector, pathogen, and reservoir ecology, which could contribute to changes in the range limits, the intensity of disease transmission and, under some circumstances, the risk of emergence and re-emergence of pathogens affecting commercial poultry.However, the role of wild birds in the perpetuation of disease is unclear. Even if climate change increases the introduction of zoonotic and bird-borne pathogens into Canada, it is difficult to predict whether this will increase the occurrence of diseases in poultry. It is likely that outbreaks will become more unpredictable, which will complicate efforts to identify periods and areas of high risk. Efforts to manage and control these events in the face of climate change will require proper biosecurity measures, in addition to more consistent surveillance of sentinel and high-risk carrier species to avert the potential risk of diseases dispersing into Canada.

Temperature-related duration of aquatic stages of the Afrotropical malaria vector mosquito Anopheles gambiae in the laboratory.

Vector abundance is an important factor governing disease risk and is often employed when modelling disease transmission. The longevity of the aquatic stages of mosquitoes (Diptera: Culicidae) dictates the rate of production of adults and hence the intensity of disease transmission. We examined how temperature influences the survival of larval stages (larvae and pupae) of Anopheles gambiae Giles sensu stricto and subsequent adult production of this most efficient malaria vector. Groups of 30 mosquitoes were reared at constant temperatures (from 10 to 40 degrees C) from the first instar and observed until death or metamorphosis of the last individual. Larvae developed into adults at temperatures ranging from 16 to 34 degrees C. Larval survival was shortest (< 7 days) at 10-12 degrees C and 38-40 degrees C, and longest (> 30 days) at 14-20 degrees C. Within the temperature range at which adults were produced, larval mortality was highest at the upper range 30-32 degrees C, with death (rather than adult emergence) representing over 70% of the terminal events. The optimal survival temperatures were lower than the temperatures at which development was quickest, suggesting a critical relationship between temperature and the life cycle of the insect. These data provide fundamental information about An. gambiae s.s. adult productivity at different temperatures, which may facilitate the construction of process-based models of malaria risk in Africa and the development of early warning systems for epidemics.

Epidemiological Interference

Wherever intensity of disease transmission (size of virus populations) is great, there will be competition among the different viruses for soil. This competition, which is discussed here as epidemiological interference, was seen in a series of studies in West Bengal, India, and in Nepal. Competition for space led to localization of adenovirus types. Competition at different seasons led to striking variation in seasonal prevalence. Competition for soil and delay in natural immunization led to postponement of infection with childhood diseases to adulthood. Finally, the same phenomenon can explain the early continued high prevalence of poliomyelitis virus in children during the first six years of life in rural West Bengal (12).