Quyen Vu Lice Outbreaks: Transmission and Avenues for Treatment Introduction & Title Slides (Slides 1, 2) Goal/Thesis (Slide 3) 1. Understanding the differences between three types of lice: how to tell them apart, and the relevant/appropriate strategies for treatment and prevention for each type. (Mostly in the first part of the presentation) 2. Humanitarian crises: how body lice are a serious issue due to disease risk. Three main diseases carried by body lice. High risk for mortality. Explained in more detail in a Burundi case study. Vector Biology (Slide 4) Head lice found anywhere on the head (typically hair, but also can be found on the eyebrows.) Body lice: typically found on the clothing, except when they need a blood meal. They then move to the skin (but usu found on the clothing NOT the skin) Pubic lice: usu found in pubic hair but are adapted to any other type of coarse hair (armpit region etc.) All of the lice types are six-legged Differ on the basis of morphology (see pictures, especially pubic lice), where they can be found as discussed above, and size Photo Credit and Source: CDC Vector Biology (Slide 5) Ectoparasite: lives on surface of host, as opposed to inside the body (endoparasite) as with many other parasites we’ve seen. Do need blood meals to survive.
Quyen Vu Move by crawling: as opposed to flying or hopping, which affects the control and prevention measures needed. Feet are specifically adapted to human hair (cannot survive for that long if they fall off a human.) They can only live 1-2 days if they fall off of a human host. See photo on the top right of the slide for a zoomed-in look at the hooks on louse feet adapted to clinging to human hair. Humans as only host. There is no animal reservoir, which makes control measures different and potentially simpler than other parasites. Photo Credit and Source: CDC Lice Life Cycle (Slide 6) 1. Egg/nit The egg/nit is usually located no more than 1/4 inches from the base of the human hair scalp. It's attached by a sticky glue-like substance secreted by the adult louse, which is what allows it to stick to the human hair. Takes 8-9 days to hatch. 2. Nymph There are three molting stages. Takes the nymphs approximately one week in total to move into the adult stage. The nymphs must take a blood meal in order to move on the next molting stage (therefore need three blood meals in total.) 3. Adult stage.
Quyen Vu Can live up to 30 days on the human host. Die within 1-2 days without the human host. All adult lice need a blood meal in order to survive (nutrients). Females need it in particular for oviposition.
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- Fall '19
- Head louse, Pediculosis, Body louse, lice, Louse, Quyen Vu