A trichinellosis outbreak: a teaching case-study
Hawraa Sweidan, Nada Ghosn
Corresponding author: Hawraa Sweidan, Epidemiological Surveillance Program, Ministry of Public Health (MOPH), Beirut, Lebanon 
Received: 03 Jan 2025 - Accepted: 30 Oct 2025 - Published: 27 Feb 2026
Domain: Epidemiology
Keywords: Trichinellosis, outbreak, investigation, analysis
Funding: This work received no specific grant from any funding agency in the public, commercial, or non-profit sectors.
This article is published as part of the supplement Teaching Case Studies in Field Epidemiology and Public Health for the Eastern Mediterranean Region, commissioned by Eastern Mediterranean Public Health Network (EMPHNET).
©Hawraa Sweidan et al. Pan African Medical Journal (ISSN: 1937-8688). This is an Open Access article distributed under the terms of the Creative Commons Attribution International 4.0 License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Cite this article: Hawraa Sweidan et al. A trichinellosis outbreak: a teaching case-study. Pan African Medical Journal. 2026;53(1):11. [doi: 10.11604/pamj.supp.2026.53.1.46359]
Available online at: https://www.panafrican-med-journal.com//content/series/53/1/11/full
PDF in process Case study 
A trichinellosis outbreak: a teaching case-study
A trichinellosis outbreak: a teaching case-study
Hawraa Sweidan1,&, Nada Ghosn1
&Corresponding author
On December 4, 2023, the local authorities notified a suspected outbreak of trichinellosis in Jahliyeh [Mount-Lebanon], having approximately 6000 residents. We investigated to identify the outbreak source, estimate the magnitude, and implement preventive measures. We defined a suspected case as a Jahliyeh resident who experienced at least three symptoms [fever, myalgia, oedema, and/or hypereosinophilia], or was diagnosed by a physician, after October 1, 2023. We inspected local butcher shops and searched for suspected cases who have visited health facilities for case management or medical advice. We described suspected cases by demographic characteristic, symptoms, and possible exposures. We tested leftover food samples at the Lebanese Agriculture Research Laboratory. During November - December 2023, a total of 146 suspected cases were identified, with one case confirmed via a positive muscle biopsy. Of 44 cases tested, 20 had hyper-eosinophilia [> 500]. Thirty percent (30%) [n=43] cases were hospitalized. The median age of cases was 38 years [range: 2-82], 59% were female. Almost all cases [n=144] reported purchasing meat from local butcher shop, with 86% [n=126] consuming beef or lamb but abstaining from pork, and 12% [n=18] consuming pork. Additionally, 41% [n=60] reported consuming the meat uncooked, while 48% [n=71] consumed it either fried or barbecued. Inspection of the butcher shop revealed inadequate hygiene practices and improper meat storage. Both minced and sausage beef samples contained Trichinella. Our preliminary investigation suggested that contaminated beef was the vehicle of infection. The butchers were likely mixing untested pork with other types of meat. We recommend training butchers on food safety and meat handling along with regular inspections. Additionally, we recommend educating the local communities on the risk associated with raw meat consumption.
General instructions: this case study should be used as adjunct training material for novice epidemiology trainees to reinforce the concepts taught in prior lectures. The case study is ideally taught by a facilitator in groups of about 20 participants. Participants are to take turns reading the case study, usually a paragraph per student. The facilitator guides the discussion on possible responses to questions. The facilitator may make use of flip charts to illustrate certain points. Additional instructor's notes for facilitation are coupled with each question in the instructor's guide to aid facilitation.
Audience: this case study was developed for novice field epidemiology students. These participants are commonly health care workers working in the county departments of health whose background may be as medical doctors, nurses, environmental health officers or laboratory scientists who work in public health-related fields. Most have a health science or biology background.
Prerequisites: before using this case study, participants should have received lectures on disease surveillance and outbreak investigation.
Materials needed: Flash drive, flip charts, markers, computers with R and R Studio
Level of training and associated public health activity: Novice - Outbreak investigation
Time required: 3-4 hours
Language: English
- Download the case study student guide;
- Request the case study facilitator guide.
The authors declare no competing interests.
We wish to acknowledge the Eastern Mediterranean Public Health Network (EMPHNET) for their support to develop this case study.
Figure 1: trichinellosis causal agents life cycle
Figure 2: map of localities in Lebanon
Figure 3: sample outbreak report
- CDC. Trichinellosis (trichinosis). CDC. 10 Sept 2024. Accessed on 10 Apr 2025.
- Prashanth Rawla, Sandeep Sharma. Trichinella spiralis Infection(Archived). 1 August 2023. Accessed on 10 Apr 2025.
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