Table 1
Evidence for incrimination of flies as vectors of trachoma
| Summary of Barnett’s Criteria | Evidence for accepting criterion |
|---|---|
| I Effective contact under natural conditions | (A) Frequent fly eye contacts shown in the Gambia (3 every 15 minutes)4 |
| (B) Children with infective discharge had double the fly eye contacts4 | |
| (C) Greater than 90% of fly eye contacts were Musca sorbens 4 | |
| II Convincing temporal and geographic association of the presence of vector and infection | (A) Musca sorbens recorded in areas of Australia, Africa, and the Middle East affected by trachoma7 |
| (B) High fly densities associated with outbreaks of trachoma7 | |
| (C) Pilot interventional study showed a significant reduction in trachoma following decrease in fly prevalence and fly eye contacts after pesticide application6 | |
| III Vector harbours pathogen | ? |
| IV Experimental transmission | Flies shown capable of transmitting Chlamydia spp between guinea pigs under experimental conditions8 |
