Tick (Acari: Ixodidae) ecological studies in Tanzania

1986 ◽  
Vol 76 (2) ◽  
pp. 229-246 ◽  
Author(s):  
R. J. Tatchell ◽  
E. Easton
Keyword(s):  
Seasonal Variation ◽  
Host Density ◽  
Dar Es Salaam ◽  
Rhipicephalus Appendiculatus ◽  
Amblyomma Variegatum ◽  
The Other ◽  
Theileria Parva ◽  
Ecological Studies ◽  
Adult Abundance

AbstractTicks were regularly collected from cattle along transects in Sukumaland and the Southern Highlands, Tanzania, and from locations near Tabora, Mbeya, Arusha and Dar es Salaam from 1973 to 1976. Marked seasonal variation in abundance occurred in Rhipicephalus appendiculatus Neumann in the Southern Highlands (but not in Sukumaland) and in Amblyomma variegatum (F.) near Tabora. It was possible to detect Theileria parva antibodies in cattle sera from the Southern Highlands only during the season of R. appendiculatus adult abundance. Despite this there was no evidence of enzootic instability of the disease. The results demonstrate that the behaviour and distributions of these and the other species of ticks found are not fixed and constant but vary according to a complicated interplay of factors as yet imperfectly understood, such as climate and vegetation and host density, susceptibility and grazing habits.

Ecological studies of ixodid ticks (Acari, Ixodidae) in Zambia. I. Cattle as hosts of the larvae of Amblyomma variegatum (F.) and Rhipicephalus appendiculatus neum.

1976 ◽  
Vol 66 (1) ◽  
pp. 65-74 ◽  
Author(s):  
John MacLeod ◽  
M. H. Colbo
Keyword(s):  
Sampling Method ◽  
Rhipicephalus Appendiculatus ◽  
Amblyomma Variegatum ◽  
The Body ◽  
Ixodid Ticks ◽  
Significant Shift ◽  
Immature Stages ◽  
Ecological Studies ◽  
Alternative Hosts ◽  
Patch Sampling

AbstractThe roles of cattle and alternative hosts in maintaining the immature stages of Amblyomma variegatum (F.) and Rhipicephalus appendiculatus Neum. are unknown. Weekly collections of ticks from cattle in two herds in Zambia indicated an apparently higher nymph-adult ratio in the annual totals for A. variegatum than for R. appendiculatus. The larva-nymph ratios for these herds were estimated by a patch-sampling method in which all larvae and nymphs on 100 cm2 areas on the cheek, neck, dewlap, shoulder, ribs, abdomen and lower-foreleg were collected. The overall annual ratios of larvae to nymphs on the two herds were: A. variegatum 5:1 and 14:1, R. appendiculatus 1·5:1 in both herds. The ratios suggest that cattle themselves feed larvae of A. variegatum in sufficient numbers to maintain their nymphal infestation level. The numbers of cattle-fed larvae of R. appendiculatus may not be adequate for this, and alternative hosts may play an important part in maintaining the population at existing levels. There was negligible evidence of significant shift of distribution of the immature stages over the body with advancing season, and it is suggested that patch-sampling affords a method of quantitative comparison of the relative infestations by the immature stages of ticks.

The ability of Rhipicephalus appendiculatus (Acarina: Ixodidae) stocks in Kenya to become infected with Theileria parva

1992 ◽  
Vol 82 (3) ◽  
pp. 349-353 ◽  
Author(s):  
S.S. Kubasu
Keyword(s):  
Salivary Glands ◽  
Rhipicephalus Appendiculatus ◽  
The Other ◽  
Laboratory Population ◽  
Theileria Parva ◽  
European Breed

AbstractEight steers of European breed, Bos taurus type which were shown to be negative for antibodies against Theileria parva, were divided into two groups of four animals each. Animals in one group were inoculated with 0.5 ml undiluted tick-derived T. p. parva Muguga strain and animals in the other group were inoculated with 1 ml undiluted tick-derived T. p. parva Kilae strain to infect them. The two infected groups of cattle were simultaneously infested with uninfected nymphal Rhipicephalus appendiculatus Neumann in separate cloth patches. Ticks were from five populations, i.e., four from different geographical zones in Kenya and one laboratory population, in separate cloth patches. After moulting, the adult ticks were fed on rabbits for three days and their salivary glands were examined by microscopy for infective stages of the parasite. This revealed significant differences in the five populations as regards to their susceptibility to Theileria parva parasites.

Epidemiology of East Coast fever: some effects of temperature on the development of Theileria parva in the tick vector, Rhipicephalus appendiculatus

Parasitology ◽  
1981 ◽  
Vol 83 (1) ◽  
pp. 199-211 ◽  
Author(s):  
A. S. Young ◽  
B. L. Leitch
Keyword(s):  
Salivary Gland ◽  
East Coast ◽  
Rhipicephalus Appendiculatus ◽  
The Other ◽  
Theileria Parva ◽  
Rate Of Development ◽  
Tick Vector ◽  
Laboratory Colony ◽  
Moult Period ◽  
Effects Of Temperature

SUMMARYThe moulting behaviour of nymphal Rhipicephalus appendiculatus from the laboratory colony and 3 field strains from Kenya was greatly influenced by constant temperatures between 18 and 37 °C but was not significantly different for the 4 tick strains. Six batches of R. appendiculatus (Muguga laboratory) nymphs which had engorged on cattle parasitaemic with 4 stocks of Theileria parva (Kiambu 4, Kiambu 5, Muguga and Mbita 4) isolated in Kenya were incubated at constant temperatures between 18 and 37 °C during their pre-moult and post-moult periods. The Theileria infections in the salivary glands of the resultant adult ticks were assessed by staining with Feulgen's stain. Two stocks (Muguga and Kiambu 5) developed their highest infections in ticks incubated at 28 °C while the other two (Kiambu 4 and Mbita 4) developed their highest infections at 23 °C. Constant temperatures of 18, 33 and 37 ° C were detrimental to the development of salivary gland infections. Temperature influenced the rate of development and numbers of the earlier Theileria stages in the ticks. Engorged nymphal ticks incubated for 4 days at 37 °C during their pre-moult period developed lower infections than ticks exposed at 4 °C for 4 days.

Some effects of irradiation on the tick Rhipicephalus appendiculatus

Parasitology ◽  
1972 ◽  
Vol 64 (3) ◽  
pp. 429-440 ◽  
Author(s):  
R. E. Purnell ◽  
J. D. Dargie ◽  
B. Gilliver ◽  
A. D. Irvin ◽  
M. A. Ledger
Keyword(s):  
Life Cycle ◽  
East Coast ◽  
Survival Rates ◽  
Rhipicephalus Appendiculatus ◽  
East Coast Fever ◽  
The Other ◽  
Theileria Parva ◽  
Sterile Male ◽  
Effects Of Irradiation On

Groups of Rhipicephalus appendiculatus ticks were given single doses of irradiation (range 0·25–16 krad) at different stages in their life-cycle: unfed nymphs, engorged nymphs, moulting nymphs and unfed adults. The effects of irradiation were assessed by evaluating the subsequent performances of the ticks when fed on rabbits. Observations were carried through until the viability of egg batches from surviving females had been recorded. Irradiation of unfed and engorged nymphs produced similar effects on the ticks, whilst irradiation of moulting nymphs and adults produced effects which were different from those produced on the other two groups but similar to each other. Ticks were in general unaffected at irradiation doses below 2 krad, but at this level and above, survival rates, mean engorged weights, percentage egg weights and viability of eggs were reduced, and feeding times were extended. Male ticks appeared to be more susceptible to the effects of irradiation than female ticks. Males irradiated at 4 krad were sterile, but since they survived doses considerably higher than this they might well prove suitably competitive in further trials should a sterile male release be considered feasable. The possibility is also considered of irradiating Theileria parva parasites in ticks and thus altering the parasites in some way that could be used in studies of immunisation of cattle against East Coast fever.

Function of coprophagous beetles (Coleoptera: Scarabaeidae, Geotrupidae, Hydrophilidae) in cattle pastures inferred from pitfall trapping data

2010 ◽  
Vol 27 (2) ◽  
pp. 85-91 ◽  
Author(s):  
Martin Šlachta ◽  
Jan Frelich ◽  
Tomáš Tonka
Keyword(s):  
Seasonal Variation ◽  
Spatial Variation ◽  
Dry Weight ◽  
Seasonal Distribution ◽  
The Other ◽  
Pitfall Trapping ◽  
Other Hand ◽  
Nested Anova ◽  
Species Groups ◽  
Dung Decomposition

Function of coprophagous beetles (Coleoptera: Scarabaeidae, Geotrupidae, Hydrophilidae) in cattle pastures inferred from pitfall trapping dataAn analysis of data on the dry weight biomass of coprophagous beetles in standardized dung (4.5 l) was conducted in order to characterize the spatial and the seasonal distribution of the beetles' biomass in cattle pastures and to elucidate their function in dung decomposition. Nested Anova with factors of farm, site (nested in farm), seasonal period and year was used to evaluate the effect of these factors on the biomass of four functional species groups: the dung dwellers ofScarabaeidae(subfamilyAphodiinae), the dung dwellers ofHydrophilidae, the small tunnellers ofScarabaeidae(subfamilyCoprinae) and the large tunnellers ofGeotrupidae. The spatial variation of biomass (between the sites and the farms) was insignificant (P>0.05) in the two dung-dweller groups and in the large-tunnellers group. On the other hand, a significant (P<0.05) seasonal variation of biomass was found in all but the large tunneller group. In dung dwellers, the spring biomass was formed mainly by two species,Aphodius prodromusandA. sphacelatus. In summer, most of the biomass was accounted for bySphaeridium lunatum, S. scarabaeoidesandA. rufipes. In the two tunneller groups,Onthophagus fracticornis, Geotrupes stercorariusandG. spinigerformed a majority of the biomass in dung.

scholarly journals THE EPIDEMIOLOGY OF PNEUMOCOCCUS INFECTION

1931 ◽  
Vol 53 (4) ◽  
pp. 535-552 ◽  
Author(s):  
Leslie T. Webster ◽  
Thomas P. Hughes
Keyword(s):  
Seasonal Variation ◽  
Host Resistance ◽  
The Other ◽  
Colony Morphology ◽  
Type Transformation ◽  
Wide Ph Range ◽  
Adults And Children ◽  
Nasal Passages ◽  
Ph Range

1. Pneumococci were obtained at one time or another from the nasal passages or throats of 80 per cent of 105 adults and children studied. In adults, they were obtained more frequently from the throat; in children, as often from the nasal passages as from the throat. 2. Of 500 pneumococcus strains studied, 97 per cent proved to be serologically specific. They formed smooth colonies and were for the most part avirulent for mice. Types I and II were obtained from one and two individuals respectively on one occasion only. Type III was obtained from nine individuals; Type XIII from nine individuals; Type XVI and Type XVIII from three individuals, for varying periods in each case. Atypical pneumococci were secured from 13 persons on single and scattered occasions. They varied in colony morphology, did not kill mice, or agglutinate in saline, but flocculated in all types of antipneumococcus sera employed and over a wide pH range in acid buffers. Their occurrence was apparently not associated with any type-transformation or virulence-enhancement process in vivo. 3. Strains of pneumococcus obtained on successive cultures from a given carrier were, with rare exceptions, of the same serological type and were similar in colony morphology, virulence for mice, and other tested biological characteristics. 4. Pneumococci of Types I and II were obtained under conditions suggestive that they lacked a capacity to spread readily; pneumococci of Types III and XIII, on the other hand, were obtained under conditions suggestive that they were spreading from person to person. 5. The persons studied differed consistently with respect to the occurrence of pneumococci. Some were pneumococcus-free, some were transient carriers, some periodic, and some chronic carriers. Data are given which suggest that the differences were due to variations in host resistance. 6. The incidence of pneumococci in all individuals studied underwent a seasonal variation paralleling that of coryza and sore throats in the same persons.

scholarly journals Seasonal variation of the plerocercoid ligula intestinalis (L) observed in roach (Rutilus rutilus, L) from the yenice irrigation pond, Çanakkale, Turkey

2004 ◽  
Vol 58 (1-2) ◽  
pp. 127-133 ◽  
Author(s):  
Cemal Oguz ◽  
Öztürk Oguz ◽  
Hayati Güre
Keyword(s):  
Seasonal Variation ◽  
Parasite Species ◽  
Abdominal Cavity ◽  
Rutilus Rutilus ◽  
The Other ◽  
Host Fish ◽  
Roach Rutilus Rutilus ◽  
Mean Intensity ◽  
Ligula Intestinalis ◽  
Irrigation Pond

This study was carried out at the Yenice Irrigation Pond between October 1999 and October 2000. For this study 368 roach (Rutilus rutilus) were examined and 37 parasites and 93 Ligula intestinalis were found in the abdominal cavity of the host (prevalence 10.1%, mean intensity 2.51 specimens/fish). Based on season, the highest number of infected fish occurred during summer (33.3%, 4 parasite/fish), and during the other season the mean intensity of infection was relatively low (prevalence 3.3%, 1 specimens/fish). On the other hand, the parasite species was determined especially on small and medium host fish sizes (2.17-100%). Basic criteria for the assessment of the parasite species of host fish were the general parameters related to parasite populations, which are prevalence, mean intensity, seasonal variation, and relationship between host size and infection.

scholarly journals Gridlocked in the city: kinship and witchcraft among Wayao street vendors in Dar es Salaam, Tanzania

Africa ◽  
2018 ◽  
Vol 88 (S1) ◽  
pp. S51-S71 ◽  
Author(s):  
Alexis Malefakis
Keyword(s):  
Social Relations ◽  
Urban Economy ◽  
Dar Es Salaam ◽  
The Other ◽  
Heterogeneous Environment ◽  
Street Vendors ◽  
Kinship Relations ◽  
The One ◽  
The City

AbstractFor a group of Wayao street vendors in Dar es Salaam, Tanzania, kinship relations were simultaneously an advantage and a hindrance. Their migration to the city and entry into the urban economy had occurred along ethnic and kinship lines. But, as they perceived the socially heterogeneous environment of the city that potentially offered them opportunities to cooperate with people from different social or ethnic backgrounds, they experienced their continuing dependency on their relatives as a form of confinement. Against the backdrop of the city, the Wayao perceived their social relations as being burdened with an inescapable sameness that made it impossible to trust one another. Mistrust, contempt and mutual suspicion were the flip side of close social relations and culminated in accusations ofuchawi(Swahili: witchcraft). However, these accusations did not have a disintegrative effect; paradoxically, their impact on social relations among the vendors was integrative. On the one hand,uchawiallegations expressed the claustrophobic feeling of stifling relations; on the other, they compelled the accused to adhere to a shared morality of egalitarian relations and exposed the feeling that the accused individual was worthy of scrutiny, indicating that relationships with him were of particular importance to others.

Seasonal Variation of Radon Daughters Concentrations in the Atmosphere and in Precipitation at the Japanese Coast of the Sea of Japan

1988 ◽  
Vol 24 (1-4) ◽  
pp. 93-95 ◽  
Author(s):  
T. Nishikawa ◽  
S. Okabe ◽  
M. Aoki
Keyword(s):  
Seasonal Variation ◽  
Sea Of Japan ◽  
Coastal Region ◽  
The Other ◽  
The Sea Of Japan ◽  
Heavy Snowfall ◽  
Air Masses ◽  
Japanese Coast ◽  
Radon Daughters ◽  
Atmospheric Radon

Abstract The atmospheric radon daughters concentration at Fukui in the Japanese coastal region of the Sea of Japan shows a seasonal variation whose high values appear in summer and low values in winter. On the other hand, the radon daughters concentration in precipitation at Fukui and that in the maritime atmosphere over the Sea of Japan are high in winter and low in summer. It is concluded from these phenomena that the greater part of the continental radon and its daughters are transported by seasonal winds from Siberia and China to Japan across the Sea of Japan in winter. However, when the air masses approach the shore, the cumulonimbus grows and the heavy snowfall scavenges out the radon daughters from the air masses in large quantities at the Japanese coastal region of the Sea of Japan.

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