bioRxiv Science⌕ Search

bioRxiv · 10.1101/2024.07.16.603659

An epidemiological description of rabies outbreaks in Zambia from 2013 to 2023.

Abstract

BackgroundIn Zambia, a dog bite is the most common rabies exposure. There is limited information on rabies outbreaks in jackals in Zambia. We investigated all rabies cases in Zambia and narrowed down on jackal bites in Mungwi district to determine a temporal trend and buffer zones for rabies. MethodsThe risk of exposure included all humans and animals bitten by jackals, data were collected by interviewing jackal bite victims and collecting brain specimen samples from animals. Risk of spread was determined by estimating the distance jackals strayed into human population and the Rabies Vaccination Coverage (RVC) in the district. The RVC was determined by dividing vaccinated dogs by dog population. The incidence rate (IR) and a Sens slope was used to determine a trend of RVC and the rabies cases in Zambia. QGIS was used to produce a heatmap and rabies risk zones. Direct Fluorescent Antibody technique was used to test for rabies. ResultsZambia had recorded a total of 224 rabies cases with a mean (SD) of 22.4 (16) rabies cases and a positivity rate of 65.4% (25.7) per year from 2013 to 2022. Lusaka and Copperbelt provinces recorded the highest rabies cases. The rabies incidence rate was 2.3 rabies cases per 10,000 dogs in Zambia. The cases had reduced from 2013 to 2021 with a Sens slope of -0.74 (p = 0.02). At least 227 animal bites were recorded (two jackals and 225 dog bites) in Mungwi District. 94% (213) of the victims needed Post Exposure Prophylaxis. The victims median age was 20 (Interquartile range=12-38) years. The accumulative RVC from 2018-2022 (611/7777), was 0.11 (95% CI: -0.4-0.7, p=0.46) annual slope increase with 1.60% mean (Standard deviation = 0.34). One rabies heatmap and three risk-level zones (low, medium and high) were produced, and two jackals and one goat specimens were positive. ConclusionsA risk-based surveillance and enhanced vaccination of dogs in high-risk areas through a one health approach is critical for rabies control in Zambia.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

kachinda, w., Banda, H., Hamukale, A., Makungu, C., Ngoma, M., Chazya, R., Mataa, L., Mulenga, C., Banda, J. B., Muleya, W., Sialubanje, C., Banda, D., Sinyange, N.. 2024-07-18. An epidemiological description of rabies outbreaks in Zambia from 2013 to 2023.. https://doi.org/10.1101/2024.07.16.603659

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

Autophagic flux is increased in peripheral blood mononuclear cells in atherosclerotic vascular disease and associates inversely with adverse cardiovascular events

Background: Autophagy is a homeostatic pathway supporting stress adaptation and is dysregulated in atherosclerosis. Its potential as a biomarker or therapeutic target in atherosclerotic vascular disease (ASVD) remains incompletely defined. We measured autophagic flux in peripheral blood mononuclear cells (PBMCs) from patients with peripheral arterial disease (PAD) or carotid stenosis (CS), compared with healthy controls, and explored clinical outcome associations. Methods: Ninety-four patients with PAD or CS and 19 healthy controls were studied. Autophagic flux was quantified from fresh blood using a validated ex vivo chloroquine inhibition ELISA measuring LC3BII accumulation. Major adverse cardiovascular events (MACE) and major adverse limb events (MALE) were ascertained over a median follow up of 828 days. Results: The ASVD cohort comprised claudication (n = 16), chronic limb threatening ischemia (CLTI; n = 49), and CS (n = 29). Autophagic flux was higher in ASVD than controls (mean 281.4 vs. 182.3 ng LC3BII/mg protein/h; p < 0.0001) and remained independently associated after multivariable adjustment. Within CLTI, concurrent infection was associated with lower flux (p = 0.001), approaching control levels (p = 0.327). In CLTI, higher flux quartiles were associated with lower MACE risk, most strongly for quartile 3 (hazard ratio 0.07 vs. quartile 1, 95% CI 0.01 to 0.50; p = 0.009). Conclusion: Autophagic flux is elevated in PBMCs from ASVD patients, independent of age and sex. Attenuated flux in CLTI with concurrent infection may indicate autophagic exhaustion in advanced disease. The association between higher flux and lower MACE in CLTI suggests prognostic utility, warranting evaluation in larger prospective studies.

pathology↗

Quantitative Model of the Ocular Immune Response during Seasonal Allergic Conjunctivitis

Allergic conjunctivitis is an inflammation of the conjunctiva caused by allergen; it is common disorder affecting up to 40% of the population. In this work, we study seasonal allergic conjunctivitis (SAC), also called "hay fever eyes", which is caused by exposure to airborne pollens. We develop a mathematical model quantifying the ocular immune system response to the allergens. First, we present a simplified qualitative description of the immunopathogenesis of SAC. Then, we express each chosen immunopathological mechanism mathematically to construct a system of thirty-one ordinary differential equations. We compare summary statistics of the predicted observable immune signals to experimental measurements and find our model captures key qualitative features of SAC progression. We then compare our predicted time series of histamine concentration to symptom scores and find a strong correlation suggesting the model predicts relevant clinically trends. Next, we calibrate the model through multi-step process. We find the most influential parameters are the production and depletion rates of IL-4, and the production rates of IL-5 and IL-8. These cytokines are targeted in treatments for asthma, atopic dermatitis, and severe eosinophilic associated disorder and suggest potential therapeutic targets for SAC. Our calibrated model mimics most of the summary statistics of the experimentally observable immune signals with discrepancies for IL-5 and IL-13 indicating that additional immunopathological mechanisms could be important.

pathology↗

Dysregulated Platelet GPIb alpha - VWF Signalling in Abdominal Aortic Aneurysm formation and Progression

Background: Platelets are critical drivers of thrombo-inflammatory responses in different cardiovascular diseases. Abdominal aortic aneurysm (AAA) is a progressive, life-threatening vascular disorder mainly characterised by chronic inflammation, extracellular matrix degradation, and the formation of a platelet-rich intraluminal thrombus (ILT). Experimental and clinical evidence identified platelets as main players in AAA pathology as evidenced by elevated platelet activation and procoagulant activity that critically contribute to AAA progression. Methods: The present study investigated the contribution of glycoprotein (GP)Ib alpha, the von Willebrand factor (VWF)-binding subunit of the platelet GPIb-IX-V complex, to AAA initiation and progression in experimental AAA using the ePPE mouse model and in patients. Results: Genetic ablation of platelet GPIb alpha significantly attenuated early aneurysm expansion in experimental AAA, indicating a critical role for GPIb alpha during the initial stages of aneurysm development. This initial effect was compensated at later time points showing no differences in aneurysm progression between groups. Notably, genetic deletion of GPIb alpha induced a constitutively hyperactive platelet phenotype already in naive mice that was further amplified during experimental AAA. This elevated platelet hyperactivity was mainly due to increased GPVI activation of platelets 28 days post-surgery. To assess the clinical relevance, spatial profiles of human ILT specimens from patients with AAA were analysed. In the ILT, we detected a highly compartmentalised distribution of GPIb alpha and VWF with pronounced enrichment within the luminal layer. In parallel, circulating VWF activity as well as platelet surface expression of GPIb alpha were significantly increased in patients with AAA. Conclusion: Collectively, these findings identify a dysregulated GPIb alpha-VWF axis in human AAA pathology, mainly characterised by enhanced platelet GPIb alpha surface expression and increased activity of circulating VWF.

pathology↗