Echinococcus Infections in Man and Animals in Kenya

1. Hydatid cysts are found in more than 30 per cent of all cattle, sheep and goats in Kenya, but the disease is prevalent in man only in the semi-desert area of Turkana. Up to the time of the present investigation the life-cycle of the parasite in East Africa had not been studied, but it was suggested that wild carnivores, such as hyenas and jackals, might be the main hosts of the adult worms. 2. One hundred and forty-three carnivores, representing 23 species, have been examined. Echinococcus adults were found in 27 out of 43 domestic dogs (Canis familiaris), in three out of four hunting dogs (Lycaon pictus), in one out of nine jackals (Thos mesomelas), and in three out of 19 hyaenas (Crocuta crocuta). 3. A detailed morphological study was made of the Kenya material. After comparison with specimens from other parts of the world, it was concluded that the only species occurring in Kenya was E. granulosus, but it is possible that the minor morphological and biological differences are evidence of distinct strains. Further laboratory studies are necessary to compare the parasite from man and animals in different parts of Kenya with material from elsewhere. 4. A search was made for larval hydatids in 92 ungulates representing 18 species, and in a miscellaneous collection of nearly 2,000 rodents and primates representing a further 31 species. Only one animal was positive, a wildebeest (Gorgon taurinus). 5. The infections in the wild carnivores were all very light; only domestic dogs were heavily infected. It is concluded that the main cycle of transmission in Kenya is between dogs and domestic livestock. 6. Turkana tribesmen are the most heavily infected people in Kenya, either because the strain of parasite is more pathogenic to man in that area, or, more probably, because of the intimate contact between children and the large number of infected dogs. A particularly dangerous custom in the area is the use of dogs to clean the face and anal regions of babies when they vomit or have diarrhea. No satisfactory explanation can be given for the rarity of the disease in man in many of the other areas of Kenya where hydatids are very common in domestic animals. 7. The control of the disease will depend upon an active health-education campaign, together with the destruction of all unregistered dogs and improvement in meat hygiene.

Solar Forcing of Gulf of California Climate During The Past 2000 Yr Suggested by Diatoms and Silicoflagellates

High-resolution records of the past 2000 yr are compared in a north–south transect (28° N to 24° N) of three cores from the eastern slopes of the Guaymas, Carmen, and Pescadero Basins of the Gulf of California (hereafter referred to as the “Gulf”). Evenly-spaced samples from the varved sediments in each core allow sample resolution ranging from ∼ 16 to ∼ 37 yr. Diatoms and silicoflagellates capture the seasonal variation between a late fall to early spring period of high biosiliceous productivity, that is driven by northwest winds, and a summer period of warmer, more stratified waters during which these winds slacken and/or reverse direction (monsoonal flow). As these winds decrease, tropical waters enter the Gulf and spread northward. Individual samples represent a composite of 7 to 23 yr of deposition and are assumed to record the relative dominance of the winter vs. summer floral components. Intervals of enhanced summer incursion of tropical waters, alternating with periods of increased late fall to early spring biosiliceous productivity are recorded in all three cores. Regularly spaced cycles (∼ 100 yr duration) of Octactis pulchra, a silicoflagellate proxy for lower SST and high productivity, and Azpeitia nodulifera, a tropical diatom, occur between ∼ A.D. 400 and ∼ 1700 in the more nearshore Carmen Basin core, NH01-21 (26.3° N), suggesting a possible solar influence on coastal upwelling. Cores BAM80 E-17 (27.9° N) and NH01-26 (24.3° N) contain longer-duration cycles of diatoms and silicoflagellates. The early part of Medieval Climate Anomaly (∼ A.D. 900 to 1200) is characterized by two periods of reduced productivity (warmer SST) with an intervening high productivity (cool) interval centered at ∼ A.D. 1050. Reduced productivity and higher SST also characterize the record of the last ∼ 100 to 200 yr in these cores. Solar variability appears to be driving productivity cycles, as intervals of increased radiocarbon production (sunspot minima) correlate with intervals of enhanced productivity. It is proposed that increased winter cooling of the atmosphere above southwest U.S. during sunspot minima causes intensification of the northwest winds that blow down the Gulf during the late fall to early spring, leading to intensified overturn of surface waters and enhanced productivity. A new silicoflagellate species, Dictyocha franshepardii Bukry, is described and illustrated.