Epidemiology and Control of a Head Louse Outbreak in Ames, Iowa, 1976

At the onset of school in 1976, head lice were recognized by teachers and school nurses in the public and parochial schools in Ames, Iowa. One or more cases were identified from the 9 elementary schools and 3 secondary schools in the community. The greatest prevalence of louse infestations occurred in 2 elementary schools (1 parochial) where 16% and 14%, respectively, of the students were infested. A program was established to screen children and exclude infested individuals from class until they were effectively treated. The community was surveyed to determine the extent of infestation in each household from which at least 1 member was attending school and had a confirmed louse infestation. Data were tabulated on the incidence of louse infestations by school, grade, sex, hair color, hair length, number of persons living in homes where louse infestations were recognized and incomes of families that had infested members. Factors that contributed to louse transmission and an evaluation of an intensive community-wide control program are discussed

lxodes dammini (Acari, Ixodidae) and Borrelia burgdorferi in Iowa

A statewide study to evaluate the presence, distribution and abundance of the deer tick, Ixodes dammini, and the spirochete, Borrelia burgdorfen, in Iowa was initiated in 1989. Six hundred and seventy-one tick collections were received from health professionals, conservation employees and concerned citizens. Additional ticks were obtained by flagging, small mammal trapping and deer checks in selected areas of Iowa. Nine I. dammini were collected in 1989 from seven counties in the eastern half of the state. Six of these were tested for B. burgdorferi and all were negative. Flagging, small mammal trapping and deer checks in eastern Iowa failed to produce I. dammini in 1989. However, in May 1990 and dammini female collected by a turkey hunter in Allamakee Co. tested positive for B. burgdoiferi. Subsequent flagging in this area yielded I. dammini adults, 19% of which were infected. Additionally, I. dammini larvae and nymphs were collected from Peromyscus leucopus. This is the first evidence of I. dammini establishment and B. burgdoiferi presence in Iowa

Fox Squirrels (Sciurus niger) Develop West Nile Virus Viremias Sufficient for Infecting Select Mosquito Species

The West Nile virus (WNV) viremia and shedding profiles of 11 adult fox squirrels (Sciurus niger) infected by needle inoculation or mosquito bite were characterized. Daily mean titers (95% confidence intervals) for all squirrels on days 1 through 6 postexposure (p.e.) were: 10(1.7 (1.32.1)), 10(4.4 (4.04.8)), 10(5.3 (5.05.6)), 10(4.4 (3.94.9)), 10(2.7 (2.03.4)), and 10(1.1 (0.52.1)) plaque-forming units (PFU)/mL. The highest WNV serum titers of individual squirrels infected by needle inoculation or mosquito bite ranged from 10(4.5) to 10(6.1) and from 10(5.1) to 10(5.3) PFU/mL, respectively. Nine (82%) squirrels, including all 4 squirrels infected by mosquito bite, had WNV serum titers \u3e or =10(5.1) PFU/mL that persisted on average for 1.6 +/- 0.3 days. Infection and dissemination rates of Culex pipiens (L.) that fed on squirrels with serum titers of 10(4.4 +/- 0.1) PFU/mL were 56% and 13%, respectively. Both of these rates increased to over 80% when fed on squirrels with a mean WNV titer of 10(5.5 +/- 0.1) PFU/mL. Infection and dissemination also occurred in Aedes triseriatus (Say) but at a much lower rate. WNV was isolated from the oral and rectal cavities of all squirrels and from urine that was opportunistically collected from 5 squirrels. The largest quantity of WNV recovered from swabs of the oral cavity and urine was 10(3.1) PFU. The longest periods after exposure that WNV was isolated from the oral cavity and urine from a squirrel were 22 and 17 days p.e., respectively. WNV RNA was also detected in kidney tissue in 1 squirrel 29 days p.e., suggesting that fox squirrels can be persistently infected. Collectively these observations provide further evidence that squirrels can contribute to the natural history and epidemiology of WNV, especially in peridomestic environments

West Nile Virus Viremia in Eastern Chipmunks (Tamias striatus) Sufficient for Infecting Different Mosquitoes

Chipmunks might play a role in enzootic WNV cycles and be an amplifying host for mosquitoes that infect humans

Attraction of \u3ci\u3eAnopheles\u3c/i\u3e (Diptera: Culicidae) to Volatile Chemicals in Western Kenya

HOST ODORS PROVIDE the olfactory cues by which mosquitoes locate blood meals (Takken 1991). Houses containing humans attract significantly more Anopheles gambiae (Giles) and Anopheles funestus (Giles) than do empty houses (Haddow 1942). Carbon dioxide, as found in human breath, attracts mosquitoes (Gillies 1980, Costantini et al. 1996, Gibson et al. 1997). Volatiles in human breath other than CO2 reportedly do not play an important role in host-seeking by An. gambiae s.s.(DeJong and Knols 1995a), indicating that body odors may provide important host-location cues by which African malaria vectors identify humans as a specific mammalian host species. Our field study tested components of human body odor in combination with CO2 as potential attractants for the two primary African malaria vectors, An. gambiae and An. funestus. If attractive, these compounds may be used to increase trap effectiveness in malaria control programs

Limnological Analyses of Cutler Reservoir and Dingle Marsh with Respect to Eutrophication

Cutler Reservoir is located in Cache county, Utah and was created for the purposes of irrigation, water storage and flood control. High nutrient loading to Cutler has raised concerns about the health of this system and has resulted in it being listed on the state\u27s 303(d) list of impaired waters. The TMDL plan being drafted for Cutler lists dissolved oxygen and phosphorous as the key issues of concern. The underlying problem created by nutrient loading is eutrophication. If Cutler is to remain as a valuable source of recreation, wildlife habitat, and water for the Cache Valley we must understand the underlying processes that control the system