The prevalence of lice infesting students of primary, preparatory and secondary schools in Cairo, Egypt.

Human lice (head and body) are among the arthropod-ectoparasites of worldwide distribution. Examining students in primary, preparatory and secondary schools recorded prevalence rates of 21.86%, 30.38% and 12.94% respectively. The overall rate of the lice infestation in the three schools was 384 out of 1772 or 21.67%. The prevalence rate of lice infestation among males and females were 17.02% & 37.8% (primary school), 27.8% & 33.1% (preparatory school), and 12.0% & 13.9% (secondary school). These totaled 17.7% (males) and 30.26% (females). The overall ratio of head to body lice was 18.2:1. Consequently, lice mainly the head louse, are still a public health problem particularly among female students in the primary and preparatory schools. In the secondary school prevalence rate of the lice infestation was low. So human lice is still a community health problem.

Evaluation of four pediculicides against the head lice Pediculus h. capitis.

Four pediculicides were tested against head lice in-vitro. The LT50 for Licid ranged between 10.75 (at conc. 50%) to 25.08 (at conc. 1%). All lice died with conc. 100% within 5 minutes. With Malathion, the LT50 ranged between 4.23 to 9.3 at conc. 50% to 1% respectively. All lice died with conc. 57% within 3 minutes. With Benzanil, the LT50 ranged between 20.85 to 44.34 at conc. 50% to 1% respectively. All lice died at conc. 2.5% within 10 minutes. With Para plus, the LT50 ranged between 18.46 to 29.5 at conc. 100% to 50% respectively. All lice died with conc. 100% within 30 minutes. So, the least time needed to kill all lice was given with Malathion (3 minutes). The least dose of pediculicide needed to kill all lice was those of Benzanil (1% = 0.025) and Malathion (1% = 0.57). The whole results were discussed regarding the advantages and disadvantages of these pediculicides.

Evaluation of the in-vitro pediculicidal action of four known insecticides and three medicinal plant extracts.

Human lice is an increasing community health problem worldwide. This is particularly true among school children who spend most of their daytime in crowded areas. Four commercially known insecticides and three medicinal plant extracts were studied to evaluate their pediculicidal activities in-vitro. The best result with insecticides was achieved with malathion (Lt5o 10.396 and slope function 1.183). The best result with medicinal plant extracts was achieved with neem oil (A. indica) (Lt5o 85.27 and slope function 1.480). Although, neem oil extract was less active than malathion, yet it is more safe for human usage.

Two contagious ectoparasites in an orphanage children in Nasr City, Cairo.

Lice and scabies are the main ectoparasites transmitted by contagious, particularly among children living in crowded areas. Examination of an orphanage children (both sex, 2-6 years old), showed infestation with head louse (64.1%), body louse (53.8%) and scabies (26.9%). The results were discussed on the light of the work done before.

Use of mass vaccination with a reduced dose of REV 1 vaccine for Brucella melitensis control in a population of small ruminants.

Mass vaccination with reduced dose 1/50 Rev 1 strain live vaccine (1-2 10(9) colony forming units), administered subcutaneously, over a four and a half year period reduced the prevalence of Brucella melitensis in Kuwait's small ruminant population from 5.8% in 1993 to 2.02% in 1997. Serological test results using the Rose Bengal Plate Test, Rivanol Agglutination Test and Complement Fixation showed no evidence of persistence of positive serology in animals nine or more months after vaccination. Questionnaires and post-vaccination flock inspections found that the effects on gestation (abortions) were minimal--and not proven to be due to the vaccine. The conclusion from these findings is that mass vaccination with reduced dose Rev 1 administered by the subcutaneous route is a practical field strategy for control of Brucella melitensis.

The insecticidal activity of Cyanobacteria against four insects, two of medical importance and two agricultural pests with reference to the action on albino mice.

Acute lethal toxicity of Cyanobacteria (blue-green algae) was investigated against 3rd larval stages of Musca domestica, and Culex pipiens, and 4th larval stages of Spodoptera littoralis and Agrotis ipsilon. The LD50s were 1.94, 2.33, 7.59 and 9.10 microg for M. domestica, C. pipiens, S. littoralis and A. ipsilon respectively. The slope functions were 4,045 +/- 0.332 (M. domestica), 4.122 +/- 0.336 (C. pipiens), 4.15 +/- 0.35 (S. littoralis) and 3.72 +/- 0.34 (A. ipsilon). These LD50s markedly affected the larval, pupal and adult time of durations as well as suppressed the oviposition of the survivor adults. The LD50 didn't show any marked effect as serum acetyl cholinesterase and gave nearly the same level of AchE activity. No doubt, Cyanobacteria are safe and promising agent for insect control.

Control of brucellosis in Kuwait by vaccination of cattle, sheep and goats with Brucella abortus strain 19 or Brucella melitensis strain Rev. 1.

In Kuwait, approximately 12,000 dairy cows were vaccinated with a reduced dose of 3 x 10(9) Brucella abortus strain 19 and approximately 350,000 sexually mature sheep and goats with a reduced dose of 10(7) B. melitensis strain Rev. 1. Using the criteria of prevaccinal and postvaccinal incidences of antibodies, abortions, and human cases of brucellosis, the programme was very successful. Widespread vaccination of adult animals is the most effective method of controlling brucellosis among cattle, sheep and goats in many countries.

Rodents and their ectoparasites in Sharkia Governorate, Egypt.

Rodents serve as reservoir hosts for many parasitic and bacterial diseases which are spread to man and animals by their habits, their droppings or by their arthropod ectoparasites. Commensal (semi-domestic) rodents were collected by different methods from Sharkia Governorate over a period of one year, 1989. The trapped rodents in descending order of prevalence were Rattus norvegicus, Rattus rattus, Mus musculus and Gerbillus gerbillus. The ectoparasites were collected and identified as five species of fleas, one species of lice and one species of mites. The role of these rodents as animal reservoirs and their ectoparasites as vectors of zoonotic diseases was discussed.