SporesOne consistent feature of these parasites is the production of spores with a characteristic polar filament (see figure 1).The spore is a resistant structure that is often released into the environment and is the primary means of getting from host to host (horizonal transmission). |
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| Numerous species of microsporidians are found in Simuliidae and Chironomidae. Becnel and Andreadis (1999) indicate that almost half of the 143 described genera of microsporidians infect insects. | Figure 1. Electron Micrograph of a spore of Janacekia debaisieuxi from Simulium vittatum. A is the anchoring disk; PF is the Polar Filament; N is the Nucleus. |
Two locally common microsporidians in black flies, Janacekia and Polydispyrenia, are illustrated below along with some examples from chiromonids.
 Click on images to see electron micrograph of infected tissue. | Micrograph of a Simulium arcticum larva infected with Janacekia debaisieuxi. |
 | Micrograph of a wet mount from a Simulium vittatum larva infected with Janacekia debaisieuxi. Bar is 5 micrometers. |
 | A xenoma of P. multispora in the host larva of Simulium aureum. X is the xenoma (the infected area of organism). The bar equals 0.5 mm. |
 | Infected segment of Dicrotendipes californicus. |
