The influence of biological rhythms on host–parasite interactions

Biological rhythms, from circadian control of cellular processes to annual cycles in life history, are a main structural element of biology. Biological rhythms are considered adaptive because they enable organisms to partition activities to cope with, and take advantage of, predictable fluctuations in environmental conditions. A flourishing area of immunology is uncovering rhythms in the immune system of animals, including humans. Given the temporal structure of immunity, and rhythms in parasite activity and disease incidence, we propose that the intersection of chronobiology, disease ecology, and evolutionary biology holds the key to understanding host–parasite interactions. Here, we review host–parasite interactions while explicitly considering biological rhythms, and propose that rhythms: influence within-host infection dynamics and transmission between hosts, might account for diel and annual periodicity in host–parasite systems, and can lead to a host–parasite arms race in the temporal domain

The Drivers of Acute Seasonal Infectious Diseases.

Seasonality is a feature of all ecological systems. Earth's terrestrial and pelagic life has evolved in a highly seasonal abiotic environment with intra-annual variation in photoperiod, temperature, and precipitation, among many other abiotic and biotic factors. Seasonal aspects of mammals and birds include seasonally varying birth rates, seasonal changes in endocrine hormones, and seasonal variation in immunity. One area where seasonal biology is particularly salient is disease ecology. The mechanisms underlying the seasonality of communicable diseases are poorly understood. I propose that much of the unexplained seasonality observed in infectious disease dynamics could be attributed to seasonal biology, including (1) birth seasonality, (2) seasonal variation in immunity, and (3) seasonal cycles in parasite traits and parasite population parameters. In my dissertation, I present work on various aspects of seasonality. In Chapter II, I explored the seasonality of births in human populations and quantified the effects of birth seasonality on measles epidemics. In Chapter III, I reviewed circadian and circannual rhythms in host and parasite populations, and proposed both ecological and evolutionary models for integrating biological rhythms into the study of infectious diseases. In Chapters IV--V, I presented my in-depth ecological studies of poliovirus, a notoriously seasonal summertime infection. I explored geographical variation in polio's seasonality and tested whether human birth seasonality or transmission seasonality drove epidemics of this disease. In addition to studying polio seasonality, I revealed the connection between (i) polio's emergence and human demography, (ii) the geographical distribution of poliovirus and its persistence, and (iii) polio symptomatology and silent chains of transmission. Lastly, I highlighted the public health implications of seasonal transmission by measuring the efficacy of the two polio vaccines and discussing how seasonality can be utilized for vaccine interventions.PhDEcology and Evolutionary BiologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/113643/1/bakkerma_1.pd

Digital Epidemiology Reveals Global Childhood Disease Seasonality and the Effects of Immunization

ACKNOWLEDGMENTS. We would like to thank Fernando Gonzalez-Dominguez and Gilberto Vaughan for providing the chicken pox case reports from Mexico, and the Estonia Health Board, Department of Communicable Disease Surveillance and Control, for Estonian chicken pox case reports. KB would like to thank Mercedes Pascual, her lab, and Marisa Eisenberg for helpful comments. Jesus Cantu (research assistant, Princeton University) translated and categorized chicken pox searches from Mexico, Thailand, Australia, and the US.Peer reviewedPostprintPostprin

ZIKV_1.1.tar.gz

R-package: ZIKV. R-package containing data and functions associated with this manuscript

Preventing Zika virus infection during pregnancy by timing conception seasonally Preventing Zika Virus Infection during Pregnancy by Timing Conception Seasonally Transmission Seasonality

It has come to light that Zika virus (ZIKV) infection during pregnancy can result in transplacental transmission to the fetus along with fetal death, congenital microcephaly and/or Central Nervous System (CNS) malformations. There are projected to be > 9, 200, 000 births annually in countries with ongoing ZIKV transmission. In response to the ZIKV threat, options to the full extent of the law" 88 Aedes aegypti has seasonal variation in its ability to facilitate flavivirus transmission 89 because its abundance and competence as a vector are affected by temperature and 90 rainfal

Time-series of infected red blood cells for different Plasmodium chabaudi chabaudi clones in mice

Time-series of infected red blood cells (×10−2 μl–1) for different Plasmodium chabaudi chabaudi clones in mice (column headings 5 onwards show days). Two treatments (IgG and hu-IgG) corresponding to the relevant control groups for different experimental designs are distinguished but do not result in differences in these time-courses. Original papers in which the data were first reported, and in which controls were compared with immune-depleted hosts, are shown in the first column

Unraveling the Transmission Ecology of Polio

<div><p>Sustained and coordinated vaccination efforts have brought polio eradication within reach. Anticipating the eradication of wild poliovirus (WPV) and the subsequent challenges in preventing its re-emergence, we look to the past to identify why polio rose to epidemic levels in the mid-20th century, and how WPV persisted over large geographic scales. We analyzed an extensive epidemiological dataset, spanning the 1930s to the 1950s and spatially replicated across each state in the United States, to glean insight into the drivers of polio’s historical expansion and the ecological mode of its persistence prior to vaccine introduction. We document a latitudinal gradient in polio’s seasonality. Additionally, we fitted and validated mechanistic transmission models to data from each US state independently. The fitted models revealed that: (1) polio persistence was the product of a dynamic mosaic of source and sink populations; (2) geographic heterogeneity of seasonal transmission conditions account for the latitudinal structure of polio epidemics; (3) contrary to the prevailing “disease of development” hypothesis, our analyses demonstrate that polio’s historical expansion was straightforwardly explained by demographic trends rather than improvements in sanitation and hygiene; and (4) the absence of clinical disease is not a reliable indicator of polio transmission, because widespread polio transmission was likely in the multiyear absence of clinical disease. As the world edges closer to global polio eradication and continues the strategic withdrawal of the Oral Polio Vaccine (OPV), the regular identification of, and rapid response to, these silent chains of transmission is of the utmost importance.</p></div

Seasonal home ranges and fidelity to breeding sites among ringed seals

Population structure and patterns of habitat use among ringed seals (Phoca hispida) are poorly known, in part because seasonal movements have not been adequately documented. We monitored the movements of 98 ringed seals in the Beaufort and Chukchi seas between 1990 and 2006 using three forms of telemetry. In the winter—spring period (when the seals were occupying shorefast ice), we used radio and ultra-sonic tags to track movements above and below the ice, respectively. We used satellite-linked transmitters in summer and fall (when the seals ranged away from their winter sites) to track at-sea movements. In the shorefast ice habitat, the home ranges of 27 adult males ranged from\1 to 13.9 km2 (median = 0.628) while the home ranges of 28 adult females ranged from \1 to 27.9 km2 (median = 0.652). The 3-dimensional volumes used by 9 seals tracked acoustically under the ice averaged 0.07 (SD = 0.04) km3 for subadults and adult males and 0.13 (SD = 0.04) km3 for adult females. Three of the radio-tracked seals and 9 tracked by satellite ranged up to 1,800 km from their winter/spring home ranges in summer but returned to the same small (1–2 km2) sites during the ice-bound months in the following year. The restricted movements of ringed seals during the ice-bound season— including the breeding season—limits their foraging activities for most of the year and may minimize gene flow within the species