tg_efficacy_pt18pt19_superseded_en

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62Transitional Guidance on PT18 + PT19September 2016temperatures >30°C should be provided. A control treatment without biocide should beincluded in all laboratory trials.Simulated-use tests can be waived if a robust field trial is submitted.14.2.2.3.1 Space treatment simulated use testsIn the case of an application for a liquid for space treatment, the aerosol test method isperformed in the test chamber in the laboratory. A known number (e.g. 50-100) testinsects (females) are exposed to the space treatment. The dose sprayed in the chambershould be comparable to the label directions. The test is replicated 3 or more times. Theknockdown percentages and mortality of mosquitoes in both insecticide treatment andnegative control are determined. Ideally, a ventilated room should be used to mimic theintended use better.14.2.2.3.2 Surface treatment simulated use testsProducts for surface treatment act on the insect by tarsal contact with the treatedsurface. The product can be applied by spraying, brushing, painting, etc. according tothe label. These products are also tested in a test chamber or an experimental hut. TheWHO guideline for testing mosquito adulticides describes such a test.In the test chamber the product is applied on small surface, or on the whole chamber, ina dose rate appropriate to the label claim. A negative control should be included. Afterthe surfaces have been left to dry the test can commence. The insects are released inthe test chamber at several time points after application (or at least at the maximumresidual time claimed at the label), to show residual efficacy. After 24 hours mortality ofthe test insects is recorded. It is mandatory to report temperature and air humidity inthe test room. These should agree as much as possible with practical use conditions.14.2.2.3.3 Products to be vaporized or fogged simulated use testsNo officially recognized guidelines are available for efficacy studies with products thatshould be vaporized (heating element that heats a tablet of liquid, coils, fan driven dives,etc.) or products that should be applied in a fogging treatment. The “Large room test” isgenerally accepted. Other methods are also acceptable if they are scientifically soundand provide a clear picture of the efficacy of the product.The “Large room test” test can be performed in a non-ventilated room of 20 to 60 m 3 .When a ventilated room is used (mimics reality better in some cases) the air exchangeshould be measured (e.g. one air chamber renovation per hour). The product is appliedaccording to the intended use, allowing it to evaporate over a specified time period(depending on the label claim e.g. 9 hours).Mosquitoes are exposed to the vapour/fog at different time points, e.g. at 0, 2, 4, 6 and8 hours. At every time point a known number of female test insects (50-100) areexposed to the vapour. The test is replicated 3 or more times. A negative control shouldbe included.The knockdown percentages (KD50, KD95, KD100), mortality and, if possible, theconcentration of the active substance in the room are determined.When the label claim says that the product should be used in ventilated rooms theopening of windows and doors should be simulated in the test.14.2.2.3.4 RepellentsRepellents are products with a repellent effect and can drive away mosquitoes. Theseproducts are either applied on human or animal skin or on clothes (topical or skinrepellent) or release the active ingredient to the air (spatial repellents).This is based onthe biological activity of the evaporated active substance.
Transitional Guidance on PT18 + PT19September 201663Products with a repellent effect, which are applied on the human skin or clothes, can betested in an “arm-in-cage” simulated-use test. The repellent is applied in the specifieddose on the (bare) forearm of the test person. The forearm is subsequently exposed totest mosquitoes in a cage for 5 minutes. This should be repeated every hour, at least upto the claimed efficacy period. If one bite is received during an exposure followed byanother bite in the next exposure (confirming the first bite), the test should be stoppedand the time of the first confirmed bite recorded as the length of repellence. If bites arenot received in succession, then the test is continued and the first bite should beconsidered ‘unconfirmed’. The same test is repeated with untreated forearms of,preferably, the same test persons. For the untreated forearm, a minimum of 5 lands in 5minutes is required to qualify the test. Once 5 lands are received, the arm should beremoved to prevent excess biting. If less than 5 lands are counted in 5 minutes, then thetest should not proceed and the mosquito cage should be replaced with ‘fresh’mosquitoes. The results of treated and untreated forearms are compared.Alternative methods using rabbits are developed. The repellent solution could be applieddirectly on the skin of a rabbit on which a cage containing female mosquitoes is placed.Skin repellents can also be tested in and experimental hut, as long as the number ofmosquitoes entering the hut is not too low.Similar tests can be used for cloth in which a repellent is incorporated (treated article).Repellent effectiveness is based on protection time, that is, the time between repellentapplication and the time of 2 or more bites on the treated arm, or the first confirmed bite(a bite followed by another within 30 min.).For products with a repellent effect, which are applied in another way (not on the humanskin or clothes, for instance spatial repellents), no common protocols are available.These products can be tested in a simulated use test, for instance in an experimentalhut. The submitted data from studies are checked for completeness, based on theapplied dose per treated area. It is also checked whether the duration of exposure issufficient. If the formulation alone i.e. without the carrier (e.g. a product with a tissue ascarrier) has been tested, data on release from the carrier are also required. The studydata should provide a clear picture of the efficacy of the product.When the label claim says that the product should be used in ventilated rooms theopening of windows and doors should be simulated in the test.14.2.2.3.5 Larvicides simulated use testsIn small scale simulated-use tests, insecticide formulation can be tested in naturalbreeding sites or simulated larval breeding sites. When natural larval populations areused pre-treatment assessments of the population should done at the site (larval countby dipping technique). Depending on the protocol, eggs or larvae can be regularlyintroduced in the treated sites to evaluate the residual efficacy. Breeding sites are keptuncovered to allow wild adults to lay their eggs. The methodology of this test isdescribed in WHO guidelines (WHO/CDS/WHOPES/GCDPP/2005.13).14.2.2.4 Field trialsFor some products against mosquitoes, field trials are not required. Especially when fieldpopulations are used in the lab or in an experimental hut. However, for some productsand uses a simulated-use test cannot mimic the practical situation sufficiently (e.g.larvicides used in large swamps and lakes, aerial applications). Especially with aerialapplications the way the product is dispersed can make a difference for efficacy. In thesecases the competent authorities should require a field test.Tests are done preferably during spring and beginning of summer. In autumn populationdecline might be due to natural causes instead of the insecticide. Larvicides shouldnormally be tested in July-August when sufficient levels of Culex spp. and Aedes spp.
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