The black death past and present. 1. Plague in the 1980s

Plague Meningitis: A Systematic Review of Clinical Course, Antimicrobial Treatment, and Outcomes

Plague meningitis is a serious and often fatal manifestation of Yersinia pestis infection. In the aftermath of a bioweapon attack with Y pestis, this typically rare manifestation may develop in a substantial number of patients, particularly if treatment delays occur. Risk factors, clinical evolution, and optimal treatment strategies for plague meningitis are not well understood. We searched PubMed Central and other databases for reports of plague meningitis in any language. Articles containing descriptions of patients with plague meningitis and their treatment and outcomes were included. Among 1,496 articles identified in our search, 56 articles describing 84 cases from 1898 to 2015 met inclusion criteria. The median age of patients was 16 years (range 6 weeks to 64 years); 68% were male. Most patients (n = 50, 60%) developed meningitis following primary bubonic plague. Common signs and symptoms included fever (n = 56, 66%), nuchal rigidity (n = 38, 45%), and headache (n = 33, 36%); 29% (n = 24) of patients had focal neurologic deficits such as cranial nerve abnormalities. Almost all (n = 23, 96%) of the 24 patients who did not receive antimicrobials died, and 42% (n = 25) of the 59 patients treated with antimicrobials died. The case fatality rate of patients grouped by antimicrobial received was 50% (1 out of 2) for fluoroquinolones, 19% (4 out of 21) for aminoglycosides, 14% (2 out of 14) for sulfonamides, 11% (2 out of 18) for chloramphenicol, and 0% (0 out of 13) for tetracyclines. Plague meningitis most often occurs as a complication of bubonic plague and can cause focal neurologic deficits. Survival is more likely in patients who receive antimicrobials; tetracyclines, aminoglycosides, and chloramphenicol had the lowest associated case fatality rates.

The sex-selective impact of the Black Death and recurring plagues in the Southern Netherlands, 1349-1450

Although recent work has begun to establish that early modern plagues had selective mortality effects, it was generally accepted that the initial outbreak of Black Death in 1347-52 was a "universal killer." Recent bioarchaeological work, however, has argued that the Black Death was also selective with regard to age and pre-plague health status. The issue of the Black Death's potential sex selectivity is less clear. Bioarchaeological research hypothesizes that sex-selection in mortality was possible during the initial Black Death outbreak, and we present evidence from historical sources to test this notion.

OBJECTIVE

To determine whether the Black Death and recurring plagues in the period 1349-1450 had a sex-selective mortality effect.

MATERIALS AND METHODS

We present a newly compiled database of mortality information taken from mortmain records in Hainaut, Belgium, in the period 1349-1450, which not only is an important new source of information on medieval mortality, but also allows for sex-disaggregation.

RESULTS

We find that the Black Death period of 1349-51, as well as recurring plagues in the 100 years up to 1450, often had a sex-selective effect-killing more women than in "non-plague years."

DISCUSSION

Although much research tends to suggest that men are more susceptible to a variety of diseases caused by bacteria, viruses and parasites, we cannot assume that the same direction of sex-selection in mortality applied to diseases in the distant past such as Second Pandemic plagues. While the exact reasons for the sex-selective effect of late-medieval plague are unclear in the absence of further data, we suggest that simple inequities between the sexes in exposure to the disease may not have been a key driver.

Engineered nanoconstructs for the multiplexed and sensitive detection of high-risk pathogens

Many countries categorize the causative agents of severe infectious diseases as high-risk pathogens. Given their extreme infectivity and potential to be used as biological weapons, a rapid and sensitive method for detection of high-risk pathogens (e.g., Bacillus anthracis, Francisella tularensis, Yersinia pestis, and Vaccinia virus) is highly desirable. Here, we report the construction of a novel detection platform comprising two units: (1) magnetic beads separately conjugated with multiple capturing antibodies against four different high-risk pathogens for simple and rapid isolation, and (2) genetically engineered apoferritin nanoparticles conjugated with multiple quantum dots and detection antibodies against four different high-risk pathogens for signal amplification. For each high-risk pathogen, we demonstrated at least 10-fold increase in sensitivity compared to traditional lateral flow devices that utilize enzyme-based detection methods. Multiplexed detection of high-risk pathogens in a sample was also successful by using the nanoconstructs harboring the dye molecules with fluorescence at different wavelengths. We ultimately envision the use of this novel nanoprobe detection platform in future applications that require highly sensitive on-site detection of high-risk pathogens.

Arthropod-borne bacterial diseases in pregnancy

Arthropod-borne bacterial diseases affect more than 25,000 Americans every year and thousands more around the world. These infections present a diagnostic dilemma for clinicians because they mimic many other pathologic conditions and are often low on or absent from the differential diagnosis list. Diagnosis is particularly challenging during pregnancy, as these infections may mimic common pregnancy-specific conditions, such as typical and atypical preeclampsia, or symptoms of pregnancy itself. Concerns regarding the safety in pregnancy of some indicated antibiotics add a therapeutic challenge for the prescriber, requiring knowledge of alternative therapeutic options for many arthropod-borne bacterial diseases. Physicians, especially those in endemic areas, must keep this class of infections in mind, particularly when the presentation does not appear classic for more commonly seen conditions. This article discusses presentation, diagnosis, and treatment of the most common of these arthropod-borne bacterial diseases, including Lyme disease, Rocky Mountain spotted fever, tick-borne relapsing fever, typhus, plague, cat-scratch disease, and Carrión disease.

Humanized TLR4/MD-2 mice reveal LPS recognition differentially impacts susceptibility to Yersinia pestis and Salmonella enterica

Although lipopolysaccharide (LPS) stimulation through the Toll-like receptor (TLR)-4/MD-2 receptor complex activates host defense against Gram-negative bacterial pathogens, how species-specific differences in LPS recognition impact host defense remains undefined. Herein, we establish how temperature dependent shifts in the lipid A of Yersinia pestis LPS that differentially impact recognition by mouse versus human TLR4/MD-2 dictate infection susceptibility. When grown at 37°C, Y. pestis LPS is hypo-acylated and less stimulatory to human compared with murine TLR4/MD-2. By contrast, when grown at reduced temperatures, Y. pestis LPS is more acylated, and stimulates cells equally via human and mouse TLR4/MD-2. To investigate how these temperature dependent shifts in LPS impact infection susceptibility, transgenic mice expressing human rather than mouse TLR4/MD-2 were generated. We found the increased susceptibility to Y. pestis for "humanized" TLR4/MD-2 mice directly paralleled blunted inflammatory cytokine production in response to stimulation with purified LPS. By contrast, for other Gram-negative pathogens with highly acylated lipid A including Salmonella enterica or Escherichia coli, infection susceptibility and the response after stimulation with LPS were indistinguishable between mice expressing human or mouse TLR4/MD-2. Thus, Y. pestis exploits temperature-dependent shifts in LPS acylation to selectively evade recognition by human TLR4/MD-2 uncovered with "humanized" TLR4/MD-2 transgenic mice.

Defense Against Biological Weapons (Biodefense)

Biological warfare (germ warfare) is defined as the use of any disease-causing organism or toxin(s) found in nature as weapons of war with the intent to destroy an adversary. Though rare, the use of biological weapons has occurred throughout the centuries.

Risk communication planning for the aftermath of a plague bioattack

We create an influence diagram of how a plague bioattack could unfold and then use it to identify factors shaping infection risks in many possible scenarios. The influence diagram and associated explanations provide a compact reference that allows risk communicators to identify key messages for pre-event preparation and testing. It can also be used to answer specific questions in whatever unique situations arise, considering both the conditions of the attack and the properties of the attacked populations. The influence diagram allows a quick, visual check of the factors that must be covered when evaluating audience information needs. The documentation provides content for explaining the resultant advice. We show how these tools can help in preparing for crises and responding to them.

Effect of deletion of the lpxM gene on virulence and vaccine potential of Yersinia pestis in mice

Yersinia pestis undergoes an obligate flea-rodent-flea enzootic life cycle. The rapidly fatal properties of Y. pestis are responsible for the organism's sustained survival in natural plague foci. Lipopolysaccharide (LPS) plays several roles in Y. pestis pathogenesis, prominent among them being resistance to host immune effectors and induction of a septic-shock state during the terminal phases of infection. LPS is acylated with 4-6 fatty acids, the number varying with growth temperature and affecting the molecule's toxic properties. Y. pestis mutants were constructed with a deletion insertion in the lpxM gene in both virulent and attenuated strains, preventing the organisms from synthesizing the most toxic hexa-acylated lipid A molecule when grown at 25 degrees C. The virulence and/or protective potency of pathogenic and attenuated Y. pestis DeltalpxM mutants were then examined in a mouse model. The DeltalpxM mutation in a virulent strain led to no change in the LD(50) value compared to that of the parental strain, while the DeltalpxM mutation in attenuated strains led to a modest 2.5-16-fold reduction in virulence. LPS preparations containing fully hexa-acylated lipid A were ten times more toxic in actinomycin D-treated mice then preparations lacking this lipid A isoform, although this was not significant (P>0.05). The DeltalpxM mutation in vaccine strain EV caused a significant increase in its protective potency. These studies suggest there is little impact from lipid A modifications on the virulence of Y. pestis strains but there are potential improvements in the protective properties in attenuated vaccine strains.

Destroying the Life and Career of a Valued Physician-Scientist Who Tried to Protect Us from Plague: Was It Really Necessary?

Thomas Campbell Butler, at 63 years of age, is completing the first year of a 2-year sentence in federal prison, following an investigation and trial that was initiated after he voluntarily reported that he believed vials containing Yersinia pestis were missing from his laboratory at Texas Tech University. We take this opportunity to remind the infectious diseases community of the plight of our esteemed colleague, whose career and family have, as a result of his efforts to protect us from infection by this organism, paid a price from which they will never recover.

Evolutionary genetics: CCR5 mutation and plague protection

A recent and prevalent mutation in the chemokine receptor CCR5 in humans of northern European ancestry has been proposed to provide protection against bubonic plague. Here we infect both normal and CCR5-deficient mice with the bacterium Yersinia pestis, the cause of the plague epidemics that wiped out one-third of Europeans in the Middle Ages, and find no difference in either bacterial growth or survival time between the two groups. Unless the pathogenesis of Yersinia infection differs markedly between mice and humans, our results indicate that CCR5 deficiency in people is unlikely to protect against plague.

Climate variability and change in the United States: potential impacts on vector- and rodent-borne diseases

Diseases such as plague, typhus, malaria, yellow fever, and dengue fever, transmitted between humans by blood-feeding arthropods, were once common in the United States. Many of these diseases are no longer present, mainly because of changes in land use, agricultural methods, residential patterns, human behavior, and vector control. However, diseases that may be transmitted to humans from wild birds or mammals (zoonoses) continue to circulate in nature in many parts of the country. Most vector-borne diseases exhibit a distinct seasonal pattern, which clearly suggests that they are weather sensitive. Rainfall, temperature, and other weather variables affect in many ways both the vectors and the pathogens they transmit. For example, high temperatures can increase or reduce survival rate, depending on the vector, its behavior, ecology, and many other factors. Thus, the probability of transmission may or may not be increased by higher temperatures. The tremendous growth in international travel increases the risk of importation of vector-borne diseases, some of which can be transmitted locally under suitable circumstances at the right time of the year. But demographic and sociologic factors also play a critical role in determining disease incidence, and it is unlikely that these diseases will cause major epidemics in the United States if the public health infrastructure is maintained and improved.

Are plague pits of particular use to palaeoepidemiologists?

BACKGROUND

The demography and pattern of disease of skeletal assemblages may not accurately reflect those of the living population of which they were once a part. The hypothesis tested here was that skeletons from a mass disaster would more closely approximate to a living population than those from a conventional cemetery.

METHOD

Six hundred skeletons recovered from a Black Death plague pit in London were compared with 236 skeletons recovered from an overlying medieval cemetery. Age and sex were determined by standard anthropological means by a single observer and adjustments were made to correct for those skeletons for which either or both could not be established. An estimate of age structure of the living medieval population of London was made, using model life tables.

RESULTS

The age and sex distribution and the pattern of disease in the Black Death skeletons did not differ substantially from those in the control group of skeletons. Both assemblages tended to overestimate the numbers in the younger age groups of the model population and underestimate the numbers in the oldest age group.

CONCLUSIONS

On the evidence from this single site, a skeletal assemblage from a mass disaster does not provide a better representation of the living population from which it was derived than that from a conventional cemetery.

The use of filter paper plasticized with polyvinyl alcohol-glutaraldehyde in ELISA

F1-antigen purified from Yersinia pestis was covalently linked to 5-mm diameter filter paper discs plasticized with polyvinyl alcohol-glutaraldehyde. These discs were used both for ELISA and dot-ELISA for the detection of anti-F1 IgG in rabbits. The best conditions were achieved using 1.25 microg of F1 antigen/disc, 3% w/v skim milk in PBS as blocking agent, anti-IgG peroxidase conjugate diluted 12,000 times, and serum from rabbits immunized or not against Y. pestis, diluted 6,400 times. The absorbance values obtained from the comparative study between this procedure and conventional ELISA were not significantly different but the low cost of the reagents employed in ELISA using the filter paper discs plasticized with polyvinyl alcohol-glutaraldehyde makes this method economically attractive.

Expression of an F1/V fusion protein in attenuated Salmonella typhimurium and protection of mice against plague

A novel approach to making fusions of F1 and V antigens, which may be incorporated into a live recombinant vaccine for plague, was developed. The nucleotide sequences encoding Yersinia pestis V antigen (lcrV) and the mature form of F1 antigen (caf1) were amplified by PCR with primers which included tails. At the 3' end of caf1 and the 5' end of lcrV, the tails encoded one of three six- or eight-amino acid linkers or their complementary sequences. The DNA overlap in each linker region was used to prime a second PCR to generate three F1/V fusions, which were cloned into pUC18. The resulting plasmids expressed fusion proteins consisting of F1 and V antigens, separated by the linkers Gly-Ser-Ile-Glu-Gly-Arg, Ser-Ala-Pro-Gly-Thr-Pro or Ser-Ala-Pro-Gly-Thr-Pro-Ser-Arg. As shown by Western blotting of bacterial cell lysates with anti-V and anti-F1 sera, the level of expression and degree of degradation of the three fusion proteins was similar. To investigate the immunogenicity of F1/V, one of the plasmids, placFV6 which encoded the Gly-Ser-Ile-Glu-Gly-Arg linker, was electroporated into the attenuated Salmonella typhimurium strain SL3261 (aroA). Mice receiving two intravenous doses of 5 x 10(6) cfu SL3261/placFV6 developed serum anti-V and anti-F1 IgG titres, with similar IgG1:IgG2a isotype ratios, and T cell responses specific for V and F1 antigens. Six weeks after vaccination, mice were challenged subcutaneously with 7.4 x 10(2) or 7.4 x 10(4) LD50s of Y. pestis strain GB, and a significant degree of protection was demonstrated. These results demonstrate the potential of co-expressing Y. pestis antigens as fusion proteins to develop a live recombinant vaccine against plague.

Yersinia pestis--etiologic agent of plague

Plague is a widespread zoonotic disease that is caused by Yersinia pestis and has had devastating effects on the human population throughout history. Disappearance of the disease is unlikely due to the wide range of mammalian hosts and their attendant fleas. The flea/rodent life cycle of Y. pestis, a gram-negative obligate pathogen, exposes it to very different environmental conditions and has resulted in some novel traits facilitating transmission and infection. Studies characterizing virulence determinants of Y. pestis have identified novel mechanisms for overcoming host defenses. Regulatory systems controlling the expression of some of these virulence factors have proven quite complex. These areas of research have provide new insights into the host-parasite relationship. This review will update our present understanding of the history, etiology, epidemiology, clinical aspects, and public health issues of plague.

The use of polyvinyl alcohol glutaraldehyde as solid-phase in ELISA for plague

Discs of polyvinyl alcohol cross-linked with glutaraldehyde were synthesized under acid catalysis (H2SO4). Then, the antigen F1 purified from Yersinia pestis was covalently linked to this modified polymer. Afterwards, an enzyme-linked immunosorbent assay (ELISA) was established for the diagnosis of plague in rabbit and human. The best conditions for the method were achieved by using 1.3 micrograms of F1 prepared in 0.067 M phosphate buffer, pH 7.2, containing 1 M NaCl (PBS); anti-IgG peroxidase conjugate diluted 6,000 times and as a blocking agent 3% w/v skim milk in PBS. The titration of positive rabbit serum according to this procedure detected antibody concentrations up to 1:12,800 times. The present method, the conventional ELISA and passive haemagglutination assay are compared.

Plague surveillance in Brazil: 1983-1992

Plague caused by Yersinia pestis, has persisted in Brazil in several natural foci spread throughout rural areas in the States of Ceara, Paraiba, Pernambuco, Piaui, Rio Grande do Norte, Alagoas, Bahia, Minas Gerais and Rio de Janeiro. Nationwide surveillance of plague in Brazil based on serological testing started in 1983. We now present an update report of the examinations carried out in our laboratory from 1983 to 1992. The passive hemagglutination test for antibodies against fraction 1A antigen of Y. pestis and the passive hemagglutination inhibition control were employed for testing a total of 220,769 sera. Samples analyzed included 2,856 sera from clinically diagnosed plague cases or suspects, 49,848 sera from rodents of 24 species and 2 species of small wild carnivores (marsupials), 122,890 sera from dogs, and 45,175 sera from cats. Specific antibodies were found in 92 (3.22%) human sera; 143 (0.29%) sera from rodents of 8 species and from the two species of marsupials, 1,105 (0.90%) sera from dogs and 290 (0.64%) sera from cats. The presence of significant levels of specific anti-F1A antibodies among rodents and wild or domestic carnivores (dogs and cats) indicates that all the Brazilian plague foci remain active in spite of the absence of human cases in some of them.