Effective and sustainable prevention and control of pork tapeworm diseases in humans and pigs in Tanzania: a policy brief

Pork tapeworm (Taenia solium) is a parasite that causes serious diseases in humans and pigs. The parasite causes epilepsy in humans and is estimated to be responsible for approximately 212 deaths per year in Tanzania. The parasite costs Tanzanian society approximately USD 8 million annually due to costs for management of epilepsy caused by the parasite (USD 5 million) and losses due to condemnation of infected pork (USD 3 million). Pork tapeworm diseases are currently not a control and prevention priority in Tanzania, and collaborative efforts among relevant sectors at various levels are limited. This policy brief recommends a One Health approach for effective and sustainable control of the pork tapeworm diseases. It puts forward fourteen actionable recommendations for the country to achieve this goal

Introduction

Pork tapeworm, Taenia solium, is a hidden threat that thrives between humans and pigs. In humans, the adult parasite causes intestinal infections (taeniasis), while it can lead to tissue infections (cysticercosis) in both humans and pigs. Taeniasis occurs when someone eats infected, undercooked pork, and cysticercosis from consuming food or water contaminated with eggs of the parasite - found in the feces of humans suffering from taeniasis. When it infects the brain or spinal cord, it can cause neurocysticercosis, responsible for 30% of acquired epilepsy in highly endemic regions (1).

In areas with poor sanitation and pigs are kept free-range, this parasite is widespread. For example, in 2012, an estimated 17,853 new epilepsy cases and 212 deaths in Tanzania were linked to the pork tapeworm (2), costing the country around USD 5 million in epilepsy-related expenses and USD 3 million in pig-related losses.

To combat this, Tanzania has established a national neglected tropical disease (NTD) control program (https://www.ntdcp.go.tz/) and the National One Health Strategy (3). Laws like the Animal Disease Act of 2003, the Meat Industry Act of 2006, and the Animal Disease Regulations of 2007 (4–6) regulate meat safety, but gaps remain. For instance, there are no clear guidelines on handling infected pig carcasses, risking infected meat entering the food supply. Our research highlights that meat inspectors often use criteria for a less dangerous parasite (the beef tapeworm) when assessing pig carcasses, leading to improper handling of infected meat.

Despite these measures, pork tapeworm diseases remain highly prevalent. Recent studies found porcine cysticercosis in 7.3% to 22.3% of pigs in certain districts (7, 8) and human cysticercosis prevalence at 1.4% (9). Contributing factors include (i) inadequate resources, (ii) poor hygiene practices, (iii) lack of sector collaboration, (iv) low community awareness, (v) insufficient diagnostic tools, and (vi) absence of specific surveillance systems for these diseases.

The persistence of porcine and human cysticercosis in Tanzania could be attributed to several factors, including the following: (i) Despite the pork tapeworm diseases being included in the country’s list of NTDs affecting humans, there are no resources allocated for their prevention and control; (ii) There are limited resources to facilitate hygiene and sanitary practices, especially in rural settings; (iii) There is lack of collaboration and coordination among key sectors from community to the national level; (iv) There is low knowledge of communities and improper practices related to pork tapeworm diseases; (v) Pork tapeworm diseases are not specifically reported in the current disease surveillance systems making it difficult to realize their burdens; (vi) There is inadequate diagnostic tools and skilled personnel for pork tapeworm disease diagnosis; (vii) There is inadequate human resource and pig slaughter facilities for effective meat inspection (10); and (viii) There is no documented guideline on what should be the fate of a pig carcass infected with the pork tapeworm when confirmed during meat inspection. This leaves a loophole for potential approval of the infected carcasses for human consumption, whether intentionally or because of ignorance. In our many years of research on the pork tapeworm diseases we have noted that many meat inspectors use the criteria for bovine cysticercosis (caused by a less dangerous parasite Taenia saginata) when judging pig carcasses infected with T. solium cysticercosis.

This policy brief recommends prioritizing pork tapeworm diseases and adopting the One Health approach for effective and sustainable control.

Policy options and implications

This policy brief puts forward fourteen actionable recommendations for effective and sustainable prevention and control of pork tapeworm diseases in humans and pigs in Tanzania. The overarching recommendation is to use a One Health approach, which brings together a multidisciplinary team to tackle this complex health challenge. Implementation of the recommended actions may be insufficient due to limited resources which are also required for preventing and controlling other diseases. However, concurrent implementation of the recommended actions through the One Health approach will ensure cost-effectiveness and sustainability in the prevention and control of the pork tapeworm diseases in Tanzania.

Actionable recommendations

For effective and sustainable prevention and control of pork tapeworm diseases in Tanzania, we provide fourteen (14) recommendations with specified implementers, actions, timeline after government adoption, and measurable indicators (Table 1).

Table 1

Table 1. Recommendations for effective and sustainable prevention and control of pork tapeworm diseases in humans and pigs in Tanzania.

Conclusions

● Diseases caused by pork tapeworm (Taenia solium) have continued to affect the health and wellbeing of Tanzanians to date despite the country’s efforts in the control of neglected tropical diseases

● The persistence of these diseases is likely due to lack of specific attention (in terms of guidelines and resources) and collaboration to facilitate disease prevention and control

● This policy brief puts forward fourteen actionable recommendations for prevention and control of the pork tapeworm diseases in Tanzania and recommends implementation of the actions using a One Health approach to enhance effectiveness and sustainability of the prevention and control strategy

● Sustainable control of pork tapeworm diseases will contribute to the prevention of acquired epilepsy and reduction of economic losses in the pig industry

● This will consequently contribute to achievement of several sustainable development goals (SDGs): SDG 1 (No poverty), SDG 2 (Zero hunger), SDG 3 (Good health and well-being) and SDG 6 (Clean water and sanitation)

Author contributions

HN: Conceptualization, Methodology, Project administration, Supervision, Validation, Visualization, Writing – original draft, Writing – review & editing, Investigation, Data curation. GM: Validation, Visualization, Writing – review & editing. FM: Validation, Visualization, Writing – review & editing. CW: Validation, Visualization, Writing – review & editing. FlK: Validation, Visualization, Writing – review & editing. MK: Validation, Visualization, Writing – review & editing. AC: Validation, Visualization, Writing – review & editing. ChN: Validation, Visualization, Writing – review & editing. MN: Validation, Visualization, Writing – review & editing. IM: Validation, Visualization, Writing – review & editing. CoN: Validation, Visualization, Writing – review & editing. SM: Validation, Visualization, Writing – review & editing. BN: Validation, Visualization, Writing – review & editing. FaK: Validation, Writing – review & editing. CK: Validation, Writing – review & editing. AN: Validation, Writing – review & editing, Visualization. EM: Validation, Writing – review & editing, Investigation, Project administration, Visualization.

Funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This study was funded by the German Federal Ministry of Education and Research (BMBF) under the CYSTINET-Africa project (CYSTINET-A_1_SUA_81203596). The funder fully supported the conduct of the study.

Acknowledgments

We gratefully acknowledge the support of Microsoft Copilot, whose valuable assistance significantly contributed to the development of this manuscript. In particular, we used this AI tool to enhance the English grammar and overall clarity during the revision process.

Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Publisher’s note

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References

1. Bustos J, Gonzales AE, Saavedra H, Handali S, Garcia HH, Cysticercosis working group in Peru. Neurocysticercosis. A frequent cause of seizures, epilepsy, and other neurological morbidity in most of the world. J Neurol Sci. (2021) 427:117527. doi: 10.1016/j.jns.2021.117527

PubMed Abstract | Crossref Full Text | Google Scholar

2. Trevisan C, Devleesschauwer B, Schmidt V, Winkler AS, Harrison W, Johansen MV. The societal cost of Taenia solium cysticercosis in Tanzania. Acta Trop. (2017) 165:141–54. doi: 10.1016/j.actatropica.2015.12.021

PubMed Abstract | Crossref Full Text | Google Scholar

3. URT. Prime Minister’s Office: National One Health Strategic Plan 2022-2027. The United Republic of Tanzania (2022). Available at: sw-1677564782-NationalOneHealthStrategicPlan2022-2027.pdf (Accessed February 10, 2024).

Google Scholar

4. URT. The Animal Disease Act 2003. The United Republic of Tanzania (2003). Available at: https://faolex.fao.org/docs/pdf/tan53026.pdf (Accessed February 10, 2024).

Google Scholar

5. URT. The Meat Industry Act 2006. The United Republic of Tanzania (2006). Available at: https://faolex.fao.org/docs/pdf/tan142842.pdf (Accessed February 10, 2024).

Google Scholar

6. URT. The Animal Diseases, Regulations 2007. The United Republic of Tanzania (2007). Available at: https://www.mifugouvuvi.go.tz/uploads/publications/sw1615277333-GN-%20THE%20ANIMAL%20DISEASES%20(ANIMAL%20AND%20ANIMAL%20PRODUCTS%20MOVEMENT%20CONTROL)%20(AMENDMENT)%20REGULATIONS,%202020-2-1(1).pdf (Accessed February 10, 2024).

Google Scholar

7. Kajuna F, Mwang’onde BJ, Holst C, Ngowi B, Sukums F, Noll J, et al. Porcine cysticercosis sero-prevalence and factors associated with its occurrence in Southern Highlands, Tanzania. Sci Afr. (2022) 17:e01382. doi: 10.1016/j.sciaf.2022.e01382

Crossref Full Text | Google Scholar

8. Wilson C, Mdegela RH, Nonga HE, Makingi G, Churi AJ, Stelzle D, et al. Seroprevalence and risk factors for Taenia spp infection in pigs in Kongwa and Songwe districts, Tanzania: A cross-sectional study. Food Waterborne Parasitol. (2023) 33:e00215. doi: 10.1016/j.fawpar.2023.e00215

PubMed Abstract | Crossref Full Text | Google Scholar

9. Makingi G, Ngowi B, Mkupasi E, Wilson C, Winkler AS, Nzalawahe J, et al. Community health-education intervention trial against human Taenia solium Taeniasis/Cysticercosis in Central and Southern Zones of Tanzania. Pathogens. (2023) 12:955. doi: 10.3390/pathogens12070955

PubMed Abstract | Crossref Full Text | Google Scholar

10. Mlowe F, Karimuribo E, Mkupasi E, Churi A, Nyerere AD, Schmidt V, et al. Challenges in the diagnosis of Taenia solium cysticercosis and taeniosis in medical and veterinary settings in selected regions of tanzania: a cross-sectional study. Vet. Med. Int. (2022). doi: 10.1155/2022/7472051

PubMed Abstract | Crossref Full Text | Google Scholar

11. URT. Ministry of Water: Draft National Water Policy 2002 Version 2023. (2023). https://www.maji.go.tz/uploads/files/DRAFT%20NATIONAL%20WATER%20POLICY%202023%20.pdf (accessed October 22, 2024).

Google Scholar