The Black Death and Other Pandemics
Scott M. Jackson in Skin Disease and the History of Dermatology, 2023
Epidemic typhus is an infection with a bacterium called Rickettsia prowazekii that is transmitted from person to person by the human body louse; the bacterium resides in the feces of the louse. This louse is slightly different from the lice that infest the hair of schoolchildren. Instead, it infests the body and garments of persons of poor health and hygiene living in unclean conditions. Scratching the louse bites causes the person to rub the louse feces into the wound, thus inoculating the body with the bacterium. The signs and symptoms of typhus include fever, chills, headache, rapid breathing, body aches, cough, nausea, vomiting, confusion, and a rash. The red, petechial rash starts on the torso and spreads outward to the arms and legs. The mortality rate of untreated epidemic typhus is anywhere from 10 to 60 percent; with antibiotics, the condition is uniformly survivable. Epidemic typhus should be distinguished from endemic (murine) typhus, which occurs worldwide and is spread by the rat flea, and typhoid, a febrile condition with red spots on the skin caused by S. typhi, made famous in the twentieth century by the life and career of “Typhoid Mary.”
An Overview of Parasite Diversity
Eric S. Loker, Bruce V. Hofkin in Parasitology, 2015
An advantage of having a solid understanding of the phylogenetic relationships for both host and associated parasite lineages is that we gain insights into when and how hosts acquired their parasites. This is certainly also true for human parasites, as indicated in the following two examples. The first pertains to the sucking lice (Anoplura) that we harbor. All sucking lice are blood-feeding ectoparasites of mammals. Humans are unusual as compared to our nearest relatives for harboring lice representing two different species, each of a different genus, Pediculus humanus and Pthirus pubis. The former species is of particular note for serving as a vector of the bacterium causing epidemic typhus (Rickettsia prowazekii) and other pathogens. In contrast, chimpanzees and gorillas each harbor one sucking louse species (Pediculus schaeffi and Pthirus gorillae, respectively). A number of phylogenetic studies have ascertained both the pattern of relationships among primates, including apes, and among their sucking lice (Figure 2.22A). Such studies have also estimated the time of divergence based on the amount of sequence change occurring for both lice and primates ( Box 2.2). For example, the divergence time between Pediculus and Pthirus was estimated to occur 13 million years ago.
Chloramphenicol and Thiamphenicol
M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson in Kucers’ The Use of Antibiotics, 2017
Chloramphenicol is effective for treatment of epidemic typhus fever, scrub typhus, murine typhus, Rocky Mountain spotted fever, and Mediterranean spotted fever (Snyder and Woodward, 1970; Breitschwerdt et al., 1991; Raoult and Drancourt, 1991; Cascio et al., 1998; Cascio and Iaria, 2006). The tetracyclines are at least as effective and have lower toxicity. Chloramphenicol appears inferior to doxycycline for the treatment of Rocky Mountain spotted fever (Helmick et al., 1984; Holman et al., 2001). However, chloramphenicol is the drug of choice in pregnant women and in other patients who cannot take tetracyclines (Walker, 1995). Chloramphenicol, doxycycline, and roxithromycin (Lee et al., 2003) or azithromycin (Chanta and Phloenchaiwanit, 2015) were all equally effective in one study of children with Orientia tsutsugamushi infection. However, resistance to both tetracyclines and chloramphenicol with this organism has been described (Watt et al., 1996). Chloramphenicol provides reasonable empiric treatment for patients with fever and rash in those parts of the world where Rickettsia prowazekii is common, because it will also effectively treat meningococcal infection.
Emerging and threatening vector-borne zoonoses in the world and in Europe: a brief update
Published in Pathogens and Global Health, 2019
Eva Jánová
Bacterial order Rickettsiales causes wide range of related diseases spread by ticks, fleas, chiggers and lice. Spreading abilities, morbidity and mortality rates of Rickettsiales are high. Typhus fever caused by Rickettsia prowazekii was classified as the category B on the list of bioterrorism agents [81]. The most common rickettsiosis in Europe is Mediterranean spotted fever caused by Rickettsia conorii. Even though the disease had been endemic to Southern Italy for many years [82], it has been spreading recently [83]. This infection may represent a severe threat, as its mortality rate is about 32% [84]. Anaplasmosis caused by Anaplasma phagophytophila has also a strongly increasing and widespread occurrence in Europe [85,86]. Recently, new human rickettsial infections have been recognized in Europe [82,87]. In general, rickettsioses occurrence increases in northern countries, which had been traditionally Rickettsia free [88]. It is supposed that this increasing occurrence is associated with the rise of temperature and decreasing number of frosty days [83,89,90]. Several rickettsial vaccines were developed; however, they were difficult, expensive and very hazardous to produce [91]. There is still no approved vaccine available yet [92].
Recurrent Fevers and Neuro-ophthalmic Disorders in a Mathematical Genius
Published in Neuro-Ophthalmology, 2021
John D Bullock, Ronald E Warwar, H Bradford Hawley
Under the Tsarist regimes in Russia, a variety of infectious diseases were quite common. In order to be a candidate for Euler’s infectious organism, it must have Russian endemicity and be causative of a disease characterised by recurrent fevers and severe ocular disability, including blindness. The following categories of organisms fulfil these criteria: [1] viruses such as Epstein-Barr virus and cytomegalovirus; [2] parasites such as Plasmodium spp., Leishmania spp., and Toxoplasma gondii; and [3] bacteria such as Salmonella typhi, Rickettsia prowazekii, Orientia tsutsugamushi, Mycobacterium spp., Treponema pallidum, Borrelia spp., Yersinia enterocolitica, Bartonella henselae, Coxiella burnetii (Brill-Zinsser disease), Staphylococcus aureus/viridans streptococci/enterococci (all causing endocarditis), and Brucella melitensis.30
How relevant are in vitro culture models for study of tick-pathogen interactions?
Published in Pathogens and Global Health, 2021
Cristiano Salata, Sara Moutailler, Houssam Attoui, Erich Zweygarth, Lygia Decker, Lesley Bell-Sakyi
Most pathogenic Rickettsia spp. must be handled at BSL3, posing particular problems for studies on tick-bacterial interactions. Thus, as with highly pathogenic viruses, such as CCHFV, tick cell cultures are a useful substitute for live, intact ticks enabling a range of studies at the cellular and molecular level. Growth of Rickettsia rickettsii, causative agent of Rocky Mountain spotted fever in humans, was compared in tick (DALBE3 and IDE2) and mammalian cell lines at temperatures between 28°C and 34°C; raising the incubation temperature induced expression of rickettsial proteins in infected tick cells possibly associated with pathogenicity for mammalian cells [152]. In the absence of a louse cell line, tick (ISE6) and insect (Sf9) cell lines were used as models to analyze the effect on the proteome of Rickettsia prowazekii, causative agent of louse-borne human epidemic typhus, of growth in arthropod and mammalian environments [153]. In this study, rickettsial stress response proteins were upregulated in both arthropod cell lines and in a murine cell line, compared to levels in bacteria grown in hen egg yolk sacs, indicating possible limitations of cell cultures to model the in vivo situation. Nevertheless, comparison of siRNA expression profiles and coding transcriptomes of R. prowazekii grown in tick (AAE2) and human cell lines revealed novel siRNAs unique to arthropod cells and evidence for alternative transcription start sites used by rickettsial genes depending on the host cell environment [154]. A review of tropism in a range of pathogenic Rickettsia spp. found that the arthropod host range in vivo was reflected in the susceptibility of tick and insect cell lines in vitro, with tick-borne spotted fever group Rickettsia generally growing better in tick cells and insect-borne typhus group Rickettsia growing better in insect cells [155]. A recent study using both tick cell lines and experimentally infected vector ticks found that while two Rickettsia parkeri proteins, RickA and Sca2, played a role in actin polymerization in tick cells in vitro and in vivo, their absence did not affect patterns of R. parkeri dissemination in live, intact ticks [156].
Related Knowledge Centers
- Alphaproteobacteria
- Bacteria
- Bacterial Capsule
- Epidemic Typhus
- Obligate Parasite
- Slime Layer
- Bacillus
- Gram-Negative Bacteria
- Intracellular Parasite
- Aerobic Organism