Trends in Bacterial Pathogens of Bats:Global Distribution and Knowledge Gaps

Bats have received considerable recent attention for infectious disease research because of their potential to host and transmit viruses, including Ebola, Hendra, Nipah, and multiple coronaviruses. These pathogens are occasionally transmitted from bats to wildlife, livestock, and to humans, directly or through other bridging (intermediate) hosts. Due to their public health relevance, zoonotic viruses are a primary focus of research attention. In contrast, other emerging pathogens of bats, such as bacteria, are vastly understudied despite their ubiquity and diversity. Here, we describe the currently known host ranges and geographic distributional patterns of potentially zoonotic bacterial genera in bats, using published presence-absence data of pathogen occurrence. We identify apparent gaps in our understanding of the distribution of these pathogens on a global scale. The most frequently detected bacterial genera in bats are Bartonella, Leptospira, and Mycoplasma. However, a wide variety of other potentially zoonotic bacterial genera are also occasionally found in bats, such as Anaplasma, Brucella, Borrelia, Coxiella, Ehrlichia, Francisella, Neorickettsia, and Rickettsia. The bat families Phyllostomidae, Vespertilionidae, and Pteropodidae are most frequently reported as hosts of bacterial pathogens; however, the presence of at least one bacterial genus was confirmed in all 15 bat families tested. On a spatial scale, molecular diagnostics of samples from 58 countries and four overseas departments and island states (French Guiana, Mayotte, New Caledonia, and Réunion Island) reported testing for at least one bacterial pathogen in bats. We also identified geographical areas that have been mostly neglected during bacterial pathogen research in bats, such as the Afrotropical region and Southern Asia. Current knowledge on the distribution of potentially zoonotic bacterial genera in bats is strongly biased by research effort towards certain taxonomic groups and geographic regions. Identifying these biases can guide future surveillance efforts, contributing to a better understanding of the ecoepidemiology of zoonotic pathogens in bats.<br/

Bats, Bat Flies, and Fungi: Exploring Uncharted Waters

Bats serve as hosts to many lineages of arthropods, of which the blood-sucking bat flies (Nycteribiidae and Streblidae) are the most conspicuous. Bat flies can in turn be parasitized by Laboulbeniales fungi, which are biotrophs of arthropods. This is a second level of parasitism, hyperparasitism, a severely understudied phenomenon. Four genera of Laboulbeniales are known to occur on bat flies, Arthrorhynchus on Nycteribiidae in the Eastern Hemisphere, Dimeromyces on Old World Streblidae, Gloeandromyces on New World Streblidae, and Nycteromyces on Streblidae in both hemispheres. In this chapter, we introduce the different partners of the tripartite interaction and discuss their species diversity, ecology, and patterns of specificity. We cover parasite prevalence of Laboulbeniales fungi on bat flies, climatic effects on parasitism of bat flies, and coevolutionary patterns. One of the most important questions in this tripartite system is whether habitat has an influence on parasitism of bat flies by Laboulbeniales fungi. We hypothesize that habitat disturbance causes parasite prevalence to increase, in line with the “dilution effect.” This can only be resolved based on large, non-biased datasets. To obtain these, we stress the importance of multitrophic field expeditions and international collaborations

Circannual variation in the expression of beta 2-adrenoceptors on human peripheral mononuclear leukocytes (MNLs)

Peripheral mononuclear leukocytes (MNLs) are widely used as a tissue model in studies of beta-adrenoceptor disturbances in hypertension and asthmatic diseases. The beta 2-adrenoceptor density (Bmax), however, depends not only on the gender of the person under study and on the time of day the blood specimens are obtained. Evidence is now reported for a circannual variation in the expression of beta 2-adrenoceptor sites on peripheral MNLs. In male volunteers the 24-h mean was found to be highest in the men studied in April/May (1135 +/- 10 sites/cell) and decreased to 891 +/- 16 sites/cell in August and to 712 +r90 sites/cell in December (means +/- SE, P less than 0.01 April/May compared to December). Concomitantly the circadian amplitude increased from 17.3% +/- 6.4% of 24-h mean in April/May to 28.2% +/- 1.4% of 24-h mean in August and to 34.2% +/- 4.2% of 24-h mean in December (means +/- SE, P less than 0.05, April/May compared to December). The circadian acrophase remained constant (190 degrees +/- 30 degrees equivalent to 12 h 40 min +/- 2 h 00 min, means +/- SE)