THE FIGHT AGAINST “HUNGRY TYPHUS” BY ZEMSTVO MEDICAL STAFF IN THE PERM PROVINCE IN 1908–1914

The paper describes sanitary-hygienic, epidemiological, medical and food measures against carried out by medics during the outbreaks of typhus in 1908–1914. As this infection became a hunger marker in Russia, the object of the study is an epidemic situation in three counties (“uezd”) of the Perm province — Ekaterinburgskiy, Kamyshlovskiy, Shadrinskiy — which population constantly suffered from a crop failure. Based on the materials of “The medical and sanitary chronicle of the Perm province”, (“Vrachebno-sanitarnaya hronika Permskoy gubernii”) containing publications describing epidemics of typhus, the author considers application of the achievements of biological and medical sciences for outlining rational strategy for measures against typhus (implementation of disinfection and disinsection procedures) and identifies two organizational innovations introduced in that time. The first epidemiological teams consisting of doctors, paramedics (“fel’dsher”) and nurses were organized and sent to the epidemic focuses. These units were intended to detect, isolate and treat typhus patients, carry out disinfection and disinfestation in special temporary anti-typhoid barracks. The population began to use temporary hospitals actively, disinfect their houses and property. However, the insufficient knowledge of a transmission pathway of infection (its causative agent — Rickettsia prowazekii — and the carrier — body lice) hampered the further development of effective anti-typhoid measures and, as a result, challenged the whole complex of proposed activities.

Comparing rates of introgression in parasitic feather lice with differing dispersal capabilities

Organisms vary in their dispersal abilities, and these differences can have important biological consequences, such as impacting the likelihood of hybridization events. However, there is still much to learn about the factors influencing hybridization, and specifically how dispersal ability affects the opportunities for hybridization. Here, using the ecological replicate system of dove wing and body lice (Insecta: Phthiraptera), we show that species with higher dispersal abilities exhibited increased genomic signatures of introgression. Specifically, we found a higher proportion of introgressed genomic reads and more reticulated phylogenetic networks in wing lice, the louse group with higher dispersal abilities. Our results are consistent with the hypothesis that differences in dispersal ability might drive the extent of introgression through hybridization.

Wolbachia Endosymbiant Was Not Detected in Field Collected Population of Head and Body Lice From Iran Using Molecular Markers

Objectives Head lice infection can lead to inferiority, depression, insomnia, and lack of education, loss of social status, secondary infections, hair removal, and allergies. Body lice can carry dangerous diseases such as typhus, trench fever, and recurrent fever. Studies on lice control due to pesticides, inappropriate drug use, pesticide risks, and pesticide resistance in the lice population are needed. The study of insect symbiotic microorganisms such as Wolbachia is a new approach to control the vector-borne disease. ResultsThe presence of this bacterium was investigated in head and body lice collected from the Iranian lice population. Genomic DNA was extracted from both lice specimens and PCR assay was performed to the detection of Wolbachia infection by using Wsp, coxA, and gatB primers. All PCR results were negative for Wolbachia in comparison with positive controls. Further studies should be performed using new molecular markers to determine the Wolbachia infection of lice.

Relapsing fevers

Louse-borne relapsing fever and tick-borne relapsing fever are characterized by repeated episodes of high fever separated by afebrile periods. They are caused by Borrelia spirochaetes distinct from those responsible for Lyme borrelioses. Untreated patients may suffer as many as five (louse-borne relapsing fever) or ten (tick-borne relapsing fever) febrile relapses of decreasing severity. B. myamotoi is much less likely to relapse. Humans are the sole reservoir of epidemic louse-borne relapsing fever caused by B. recurrentis and transmitted by body lice (Pediculus humanus corporis). Endemic tick-borne relapsing fevers are caused by at least 17 different Borrelia species and have their own particular species of soft Ornithodoros, or, in the case of B. myamotoi and B. lonestari, hard Ixodes or Ablyomma tick vectors that also act as reservoirs. Transmission transplacentally, or by needlestick, blood transfusion, or laboratory accident is also possible.

A simplified protocol for in vitro rearing of human body lice

Human body lice (Pediculus humanus) are neglected ectoparasites and pathogen vectors. Difficulties in raising and maintaining colonies of body lice in a laboratory setting remain a barrier to fundamental studies of physiology and vector-pathogen interactions in these insects. Several in vivo and in vitro rearing systems have been previously described and used by multiple research groups. However, these methods suffer from drawbacks that still complicate the rearing of body lice relative to many other commonly studied hematophagous insects. Here, a simplified protocol for raising and maintaining body lice in vitro using the commercially available Hemotek apparatus is described. This protocol draws from published methods for rearing body lice as well as other hematophagous insect species to further reduce labor, time, costs, and regulatory requirements typically associated with keeping human body lice in the laboratory. Using this protocol, the insects consistently fed on commercially available rabbit blood with little mortality, reached adulthood at a high rate, and produced a significant number of viable eggs, resulting in a 4.8-fold increase in population over a period of 40 days. The data suggest that the process described here can propagate modest populations for ongoing laboratory experiments and is a useful alternative to existing methods. The use and further optimization of in vitro rearing systems may facilitate dynamic studies of body lice by a wider range of investigators, enabling new progress in combating lice infestations, and louse-borne infections.