Exploring the association of weather variability on Campylobacter - A systematic review

BACKGROUND

Previous work has found climate change-induced weather variability is suspected to increase the transmission of enteric pathogens, including Campylobacter, a leading cause of bacterial gastroenteritis. While the relationship between extreme weather events and diarrheal diseases has been documented, the specific impact on Campylobacter infections remains underexplored.

OBJECTIVE

To synthesize the peer-reviewed literature exploring the effect of weather variability on Campylobacter infections in humans.

METHODS

The review included English language, peer-reviewed articles, published up to September 1, 2022 in PubMed, Embase, GEOBASE, Agriculture and Environmental Science Database, and CABI Global Health exploring the effect of an antecedent weather event on human enteric illness caused by Campylobacter (PROSPERO Protocol # 351884). We extracted study information including data sources, methods, summary measures, and effect sizes. Quality and weight of evidence reported was summarized and bias assessed for each article.

RESULTS

After screening 278 articles, 47 articles (34 studies, 13 outbreak reports) were included in the evidence synthesis. Antecedent weather events included precipitation (n = 35), temperature (n = 30), relative humidity (n = 7), sunshine (n = 6), and El Niño and La Niña (n = 3). Reviewed studies demonstrated that increases in precipitation and temperature were correlated with Campylobacter infections under specific conditions, whereas low relative humidity and sunshine were negatively correlated. Articles estimating the effect of animal operations (n = 15) found presence and density of animal operations were significantly associated with infections. However, most of the included articles did not assess confounding by seasonality, presence of animal operations, or describe estimates of risk.

DISCUSSION

This review explores what is known about the influence of weather events on Campylobacter and identifies previously underreported negative associations between low relative humidity and sunshine on Campylobacter infections. Future research should explore pathogen-specific estimates of risk, which can be used to influence public health strategies, improve source attribution and causal pathways, and project disease burden due to climate change.

Multipathogen Outbreak of Bacillus cereus and Clostridium perfringens Among Hospital Workers in Alaska, August 2021

OBJECTIVE

Clostridium perfringens and Bacillus cereus are common causes of reported foodborne illness. On August 6, 2021, the Alaska Division of Public Health identified a multipathogen gastrointestinal outbreak among hospital staff in Homer, Alaska. The objectives of this study were to identify the outbreak source and prevent future illness.

METHODS

We conducted a retrospective cohort study of hospital staff who participated in luncheon events during August 5-7, 2021, and used an online survey to identify hospital staff with gastrointestinal illness. We defined case patients as people who reported new-onset gastrointestinal illness (diarrhea or abdominal cramping) after food consumption during the luncheon events. We calculated adjusted odds ratios of gastrointestinal illness associated with reported food exposures. We tested available food samples for C perfringens and B cereus and tested case patient stool specimens for C perfringens. We conducted an environmental investigation at the implicated vendor site.

RESULTS

Of 202 survey responses, 66 (32.7%) people reported acute gastrointestinal illness: 64 (97.0%) reported diarrhea, 62 (94.9%) reported abdominal cramps, and none were hospitalized. Of 79 people who consumed ham and pulled pork sandwiches, 64 (81.0%) met the case definition; this food item was significantly associated with increased odds of gastrointestinal illness (adjusted odds ratio = 296.4; 95% CI, 76.7-2019.1). C perfringens and B cereus were isolated at confirmatory levels from sandwich samples. C perfringens enterotoxin was detected in all 5 stool specimens tested. Environmental investigators observed other food items at the sandwich vendor that were refrigerated outside the required temperature range (>41 °F); no clear handling deficiencies for the implicated food were identified.

CONCLUSION

Quick notification and effective collaboration can help detect an outbreak, identify the responsible food vehicle, and mitigate further risk.

Using Geographic Disaggregation to Compare Tuberculosis Epidemiology Among American Indian and Alaska Native Persons-USA, 2010-2020

BACKGROUND

American Indian and Alaska Native (AIAN) populations are frequently associated with the highest rates of tuberculosis (TB) disease of any racial/ethnic group in the USA. We systematically investigated variation in patterns and potential drivers of TB epidemiology among geographically distinct AIAN subgroups.

METHODS

Using data reported to the National Tuberculosis Surveillance System during 2010-2020, we applied a geographic method of data disaggregation to compare annual TB incidence and the frequency of TB patient characteristics among AIAN persons in Alaska with AIAN persons in other states. We used US Census data to compare the prevalence of substandard housing conditions in AIAN communities in these two geographic areas.

RESULTS

The average annual age-adjusted TB incidence among AIAN persons in Alaska was 21 times higher than among AIAN persons in other states. Compared to AIAN TB patients in other states, AIAN TB patients in Alaska were associated with significantly higher frequencies of multiple epidemiologic TB risk factors (e.g., attribution of TB disease to recent transmission, previous diagnosis of TB disease) and significantly lower frequencies of multiple clinical risk factors for TB disease (e.g., diagnosis with diabetes mellitus, end-stage renal disease). Occupied housing units in AIAN communities in Alaska were associated with significantly higher frequencies of multiple measures of substandard housing conditions compared to AIAN communities in other states.

CONCLUSIONS

Observed differences in patient characteristics and substandard housing conditions are consistent with contrasting syndromes of TB epidemiology in geographically distinct AIAN subgroups and suggest ways that associated public health interventions could be tailored to improve efficacy.

The synthesis of novel matrix metalloproteinase inhibitors employing the Ireland-Claisen rearrangement

Matrix metalloproteinase inhibitors of general formula (1) were synthesised by a route involving an Ireland-Claisen rearrangement which enables systematic modification of the substituent alpha to the hydroxamic acid. An analogue (12c) possessing an alpha-cyclopentyl group is a potent broad spectrum inhibitor that displays high and sustained blood levels following oral dosing in both the rat and marmoset ex-vivo bioassays. This compound and analogues are also potent inhibitors of TNF alpha release.

Matrix metalloproteinase expression during experimental autoimmune encephalomyelitis and effects of a combined matrix metalloproteinase and tumour necrosis factor-alpha inhibitor

Matrix metalloproteinases (MMPs) are a large family of Zn2+ endopeptidases that are expressed in inflammatory conditions and are capable of degrading connective tissue macromolecules. MMP-like enzymes are also involved in the processing of a variety of cell surface molecules including the pro-inflammatory cytokine TNF-alpha. MMPs and TNF-alpha have both been implicated in the pathology associated with neuro-inflammatory diseases (NIDs), particularly multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE). We have shown that BB-1101, a broad spectrum hydroxamic acid-based combined inhibitor of MMP activity and TNF processing, reduces the clinical signs and weight loss in an acute EAE model in Lewis rats. However, little is known about which MMPs are involved in the neuroinflammatory process. In order to determine the optimum inhibitory profile for an MMP inhibitor in the treatment of NID, we investigated the profile of MMP expression and activity during EAE. The development of disease symptoms was associated with a 3-fold increase in MMP activity in the cerebrospinal fluid (CSF), which could be inhibited by treatment with BB-1101, and an increase in 92 kDa gelatinase activity detected by gelatin substrate zymography. Quantitative PCR analysis of normal and EAE spinal cord revealed the expression of at least seven MMPs. Of these, matrilysin showed the most significant change, being elevated over 500 fold with onset of clinical symptoms and peaking at maximum disease severity. Of the other six MMPs detected, 92 kDa gelatinase showed a modest 5 fold increase which peaked at the onset of clinical signs and then declined during the most severe phase of the disease. Matrilysin was localised by immunohistochemistry to the invading macrophages within the inflammatory lesions of the spinal cord. Matrilysin's potent broad spectrum proteolytic activity and its localisation to inflammatory lesions in the CNS suggest this enzyme could be particularly involved in the pathological processes associated with neuro-inflammatory disease.