Methods in Anopheles Research - MR4

Chapter 1 : Insectary Operation1.2 Cleanliness and General MaintenancePage 1 of 81.2 Cleanliness and General MaintenanceMR4 StaffIntroductionCleaning and general maintenance of insectaries can easily fall to the bottom of the list of things to do.However, daily light cleaning and routine deep cleaning help prevent serious problems such as infectionand predation. Following are some reasons a clean environment has a major impact on mosquito cultureand research results.Promotion of cleanliness and sterilityReduction of infections and pestsMost insectary infections are fungal, protozoan, or bacterial and are routinely transmitted via water or air(see Chapter 2.2). While it is not practical to completely eliminate these pathogens from the environment,it is possible to reduce their prevalence. A primary infection may not be lethal or significantly debilitate themosquitoes, but it may produce conditions that are favorable to the development of secondary infectionsthat are lethal. Often fungal infections may be chronic in nature, diminishing the immune status of larvaeresulting in a secondary, lethal bacterial infection. Microbial control can also lead to a reduction inbiogenic toxins.Minimizing insect pests in the insectary can also be crucial to maintaining healthy stocks. Insect pests,such as predatory roaches and ants, are of greatest concern in an insectary as they can easily consumea colony of adult mosquitoes overnight. Larger pests such as rodents introduce waste products thatharbor pathogens in the rearing environment. The easiest way to minimize pests in the insectary is toreduce or eliminate the conditions that attract them: food, accessible water, and harborages (shelter).Clean conditions alone are usually insufficient to prevent all pest problems. In this case, baits and trapscan be used, but be sure they do not contain insecticides to which your mosquitoes will be exposed (seebelow).Achieving sanitary conditionsAt a given period of log phase growth of a microbial population, the titer of organisms is proportional tothe titer at the beginning. Therefore, minimizing microbial growth by any means can significantly reducethe capacity for growth.Insectaries often use equipment and solutions that cannot be autoclaved or otherwise fully sterilized, norare facilities for gas or irradiation sterilization practical. Nonetheless, measures must be taken thatprovide a reduction in microbial contamination. Heat killing on surfaces and rearing equipment can bedone by boiling, autoclaving, or baking. Exposing fluids, tools and containers to even a sub-sterilizinglevel of heat can allow fewer microbes into your environment. Autoclaving is most effective, but liquidsthat contain components destroyed by autoclaving can be partially decontaminated by an elevated heatprocess such as pasteurization or filtration. Many of these treatments and practices are similar to thosepracticed in restaurants: sanitary, but not sterile conditions are the goal.Worker health and moraleA clean, pleasant-smelling, uncluttered insectary is healthier and more desirable to work in for longperiods of time, and an uncomfortable and smelly insectary is one reason people are not eager to remain.Moreover, an abundance of molds and dust are likely to irritate asthmatics and those with allergies.Techniques for Achieving Clean and Sanitary ConditionsInsectary workers must recognize that sanitation – in addition to sterilization – is an effective way topromote consistent mosquito health. We have listed many options for achieving sanitary conditions, and