Investigation 007
What the Slide Cannot Say
Three parasites cause cancer. Nobody is checking for a fourth.
Flukes & tapeworms
Schistosoma haematobium
A parasite the IARC classifies as a Group 1 human carcinogen. Infection causing cancer is established science, not a fringe claim.
What we are reading
Gathered for the investigation and not yet written up. Each note says what the paper does and does not show.
- Efared B, Bako ABA, Idrissa B, et al. Urinary bladder Schistosoma haematobium-related squamous cell carcinoma: a report of two fatal cases and literature review.10.1186/s40794-022-00161-x · PMID 35164874
Two fatal cases plus review, so weak as evidence of incidence — cite it for the mechanism and the histology, not for risk figures. States S. haematobium is a proven carcinogenic agent causing bladder SQUAMOUS cell carcinoma, which is the point: a different histology from the transitional cell cancer most bladder cancer is. Needs an IARC monograph alongside it before broadcast.
- Zaghloul MS, Zaghloul TM, Bishr MK, Baumann BC. Urinary schistosomiasis and the associated bladder cancer: update.10.1186/s43046-020-00055-z · PMID 33252773
The clinical review of the one parasite-cancer link nobody disputes. Schistosoma haematobium is an IARC GROUP 1 carcinogen — the same category as tobacco and asbestos — and the cancer it causes is usually SQUAMOUS CELL carcinoma of the bladder rather than the urothelial type the West sees. Note the honest gap they name: several carcinogenic pathways have been proposed and 'the exact mechanism(s) are not defined yet'. Group 1 does not mean the mechanism is known; it means the epidemiology is beyond argument.
- von Bülow V, Lichtenberger J, Grevelding CG, Falcone FH, Roeb E, Roderfeld M. Does Schistosoma mansoni Facilitate Carcinogenesis?10.3390/cells10081982 · PMID 34440754
The edge of the evidence, and the most useful paper for showing how IARC categories actually work. S. haematobium is Group 1 — definitely carcinogenic. S. mansoni, its close relative, is GROUP 3 — insufficient evidence to classify, which is not the same as evidence of safety. The authors argue from case reports, animal models and cell culture that mansoni may still predispose to liver and colorectal cancer. This is the honest shape of the parasite-cancer question outside the three settled organisms: a real hypothesis, a real mechanism, and a category that says nobody has done the study.
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