Rickettsial Infection in Dermacentor variabilis (Acari : Ixodidae) Inhibits Transovarial Transmission of a Second Rickettsia

This study examined the ability of ticks to maintain multiple species of spotted fever group rickettsiae via transovarial transmission. Using a capillary feeding method, previously established Rickettsia montana- and Rickettsia rhipicephali-infected cohorts of Dermacentor variabilis (Say) were exposed to R. rhipicephali and R. montana, respectively, in two reciprocal challenge experiments. Eggs collected from individual females, for two successive generations, of each cohort were assessed for rickettsial infection by polymerase chain reaction for each challenge experiment. Assessment of the eggs from challenged ticks identified that both R. montana- and R. rhipicephali-infected ticks were refractory to their respective challenge rickettsiae. The prechallenged infection rate for both F1 and F2 generations (100%) of the R. montana-infected cohort was resistant to transovarial transmission of the second rickettsia species, and only R. montana was detected in the eggs of F1 = (50%) and F2 = (74%) challenged females. The R. rhipicephali-infected cohort maintained a lower level of infection (20%) in the population and did not transovarially transmit the challenge species, however, detectable levels of infection were lost after the first generation. Second-generation ticks, no longer infected with R. rhipicephali, became susceptible to infection with R. montana and female ticks (approximate to 4%) were able to transmit R. montana to their progeny. The resistance of the ovaries to co-infection and apparent host-specific nature of infection suggests that rickettsial infection of tick ovaries may alter the molecular expression of the oocytes so as to preclude secondary infection with other rickettsiae

Susceptibility of certain wheat varieties to the infestation by Rhyzopertha dominica (F.) and Tribolium confusum (du Val)

Eight Egyptian flour wheat varieties were assessed in order to determine their appropriate level of susceptibility to Rhyzopertha dominica (F.) and Tribolium confusum (du Val). Free choice test for attraction insect adults was used in the first experiment at time interval ranged from 0.125 to 5 days post infestation. At days, results showed that the lowest attracted numbers of R. dominica adults were 5.00 and the highest ones were 22.67 for SAKL8 and SIDS1 varieties, respectively. The varieties can be arranged descendently according to the attracted numbers of R. dominica as follow: SAKL8, SAKL1, BACANORA, DEBEIRA, , GIZA168, GIZA164, SIDS6 and SIDS1. The descending order results were obtained for T. confusum could be the similar. Statistical analysis demoed significant differences between the numbers of the eight varieties. In the second experiment, the numbers of F1 and the duration of offspring of each stage were determined. Based on the Dobie Index (D.I.) for R. dominica, SAKL8, DEBEIRA, BACANORA and SAKL1 were found to be resistant varieties. While the SIDS1 and SIDS6 varieties have a moderate resistant. In the case of T. confusum all varieties showed a degree of resistance, except SAKL8 and SIDS1showed a moderate resistant. The BACANORA cultivar showed the lowest D.I. value in the two tested insect species.  The obtained results can give a better understanding to the stored-grain managers regarding to the prospective differences in wheat susceptibility to R. dominica and T. confusum infestation

VHF radar observations of the dip equatorial E-region during sunset in the Brazilian sector

Using the RESCO 50 MHz backscatter radar (2.33° S, 44.2° W, DIP: –0.5), at São Luís, Brazil, we obtained Range Time Intensity (RTI) maps covering the equatorial electrojet heights during daytime and evening. These maps revealed a scattering region at an altitude of about 108 km during the sunset period. The type of 3-m irregularity region we present here has not been reported before in the literature, to our knowledge. It was mainly observed around the Southern Hemisphere summer-solstice period, under quiet magnetic activity condition. The occurrence of this echo region coincides in local time with the maximum intensity of an evening pre-reversal eastward electric field of the ionospheric <i>F</i>-region. A tentative explanation is proposed here in terms of the theory of the divergence of the equatorial electrojet (EEJ) current in the evening ionosphere presented by Haerendel and Eccles (1992), to explain the partial contribution of the divergence to the development of the pre-reversal electric field. The theory predicts an enhanced zonal electric field and hence a vertical electric field below 300 km as a consequence of the EEJ divergence in the evening. The experimental results of the enhanced echoes from the higher heights of the EEJ region seem to provide evidence that the divergence of the EEJ current can indeed be the driver of the observed scattering region

Estimates of Dietary Mineral Micronutrient Supply from Staple Cereals in Ethiopia at a District Level

Recent surveys have revealed substantial spatial variation in the micronutrient composition of cereals in Ethiopia, where a single national micronutrient concentration values for cereal grains are of limited use for estimating typical micronutrient intakes. We estimated the district-level dietary mineral supply of staple cereals, combining district-level cereal production and crop mineral composition data, assuming cereal consumption of 300 g capita−1 day−1 proportional to district-level production quantity of each cereal. We considered Barley (Hordeum vulgare L.), maize (Zea mays L.), sorghum (Sorghum bicolor (L.) Moench), teff (Eragrostis tef (Zuccagni) Trotter), and wheat (Triticum aestivum L.) consumption representing 93.5% of the total cereal production in the three major agrarian regions. On average, grain cereals can supply 146, 23, and 7.1 mg capita−1 day−1 of Ca, Fe, and Zn, respectively. In addition, the Se supply was 25 µg capita−1 day−1. Even at district-level, cereals differ by their mineral composition, causing a wide range of variation in their contribution to the daily dietary requirements, i.e., for an adult woman: 1–48% of Ca, 34–724% of Fe, 17–191% of Se, and 48–95% of Zn. There was considerable variability in the dietary supply of Ca, Fe, Se, and Zn from staple cereals between districts in Ethiopi

Blood Biochemical Profile and Carcass Characteristics of Weaner Rabbits Fed Varying Inclusion Levels of Gamba Grass (Andropogon gayanus Kunth.) Forage

A study was conducted to investigate the effect of varying inclusion levels of Gamba grass (Andropogon gayanus Kunth) forage on haematological, blood biochemical and carcass characteristics of weaner rabbits. A total of 20 male rabbits of mixed breeds with an average initial weight of 450g were randomly assigned into four dietary treatments containing varying inclusion levels of gamba grass forage (0, 5, 10 and 15%). There were four rabbits per treatment, each serving as a replicate in a completely randomized design. Blood samples were collected at the end of eight (8) week feeding period before the carcass analysis.. Results indicated that there were significant (P<0.05) increasing trend in the haematological and blood biochemical parameters measured. There were 51% and 55% increases (P<0.05) in total protein (8.53 vs. 5.65g/dl) and calcium ions (2.65 vs. 1.18mmol/dl) in rabbits fed diet containing 15% inclusion level of gamba grass forage compared to the control. However, there were 10% and 17% decreases (P<0.05) in white blood cells (4.92 vs. 4.43%) and alkaline phosphate (89.33 vs. 76.33IU/dl) in rabbits fed the control diet than those fed diet containing 15% inclusion level of gamba grass. Also, there were 13% and 49% increase (P<0.05) in dressing percentage (54.80 vs. 48.60%) and weight of thigh (16.95 vs. 11.35%) in rabbits fed diet containing 15% inclusion level of gamba grass forage compared to the control. However, length of small intestine and weights of heart, head, stomach and small intestines were similar (P>0.05) across the treatments, respectively. It was concluded that gamba grass forage can be included up to 15% in the diet of weaner rabbits, without adverse effect on haematological, biochemical profile and carcass characteristics of the rabbits in Northern Guinea savanna of Nigeria. Gamba grass (Andropogon gayanus Kunth) forage can be included in the diets of weaner rabbits to reduce cost of production.Keywords: Blood, competition, carcass, feed, gamba, Nigeria, rabbi

ABH secretor status of students in the college of medical sciences, University of Maiduguri by inhibition method

Background: ABH blood group and secretor status of individuals are inherited independently although both may be associated with diabetes, autoimmune diseases and heart diseases. Aim: A cross-sectional study was employed to determine the ABH blood group and secretor status of students in the University of Maiduguri. Methodology: Two ml blood and 3ml saliva were collected from each study participants and were assayed independently. The ABO blood group and secretor status were determined by tube method and haemagglutination inhibition technique respectively. Results: A total of 235 apparently healthy students of the College of Medical Sciences participated in this study. Of the 235 participants, 97.4% are ABH secretors whereas 2.6% are ABH non-secretors. One hundred and nineteen 119(50.6%) of the subjects are males, of which 115 are secretors while 4 are non-secretors. Among the 116(49.4%) females who participated, 114 are secretors while 2 are non-secretors. The distribution of ABO blood group among the subjects shows that 21.3% were group A, 20.8% group B, 8.5% group AB and 49.4% group O. Conclusion: In this study, Blood group O is the commonest while AB was the least among the subjects. Overall, there are more secretors than non-secretors among the subjects. However, the study suggests that the ability to secrete ABH substances is independent of ABO blood group genes. The analysis also helps in revealing the prevalence of secretor status among the students. With the associations of disease and secretors, the secretor status of individuals may play a role in the diagnosis and management of diseases. Keywords: ABO blood group; secretor status; ABH antigen

The performance of field sampling for parasite detection in a wild passerine

Parasites can impact the behavior of animals and alter the interplay with ecological factors in their environment. Studying the effects that parasites have on animals thus requires accurate estimates of infections in individuals. However, quantifying parasites can be challenging due to several factors. Laboratory techniques, physiological fluctuations, methodological constraints, and environmental influences can introduce measurement errors, in particular when screening individuals in the wild. These issues are pervasive in ecological studies where it is common to sample study subjects only once. Such factors should be carefully considered when choosing a sampling strategy, yet presently there is little guidance covering the major sources of error. In this study, we estimate the reliability and sensitivity of different sampling practices at detecting two internal parasites-Serratospiculoides amaculata and Isospora sp.-in a model organism, the great tit Parus major. We combine field and captive sampling to assess whether individual parasite infection status and load can be estimated from single field samples, using different laboratory techniques-McMaster and mini-FLOTAC. We test whether they vary in their performance, and quantify how sample processing affects parasite detection rates. We found that single field samples had elevated rates of false negatives. By contrast, samples collected from captivity over 24 h were highly reliable (few false negatives) and accurate (repeatable in the intensity of infection). In terms of methods, we found that the McMaster technique provided more repeatable estimates than the mini-FLOTAC for S. amaculata eggs, and both techniques were largely equally suitable for Isospora oocysts. Our study shows that field samples are likely to be unreliable in accurately detecting the presence of parasites and, in particular, for estimating parasite loads in songbirds. We highlight important considerations for those designing host-parasite studies in captive or wild systems giving guidance that can help select suitable methods, minimize biases, and acknowledge possible limitations. Keywords: McMaster; fecal egg count; field sampling; mini‐FLOTAC; parasite infection; repeatability

Rocket borne instrumentation for the measurement of electron density-height profile in the ionosphere

The present paper describes the construction and working of a high frequency capacitance rocket payload for the measurement of electron concentration in the ionosphere, designed and fabricated mostly with indigenous components. This payload was flight-tested in the first and second Indian Centaure test rocket launched on 26-2-1969 and 7-12-1969 from Thumba Equatorial Rocket Launching Station. The paper also presents the calibration procedures and some of the preliminary results obtained from the first flight to show the capabilities of the instrument

Signatures of 3?6 day planetary waves in the equatorial mesosphere and ionosphere

International audienceCommon periodic oscillations have been observed in meteor radar measurements of the MLT winds at Cariri (7.4° S, 36.5° W) and Ascension Island (7.9° S, 14.4° W) and in the minimum ionospheric virtual height, h'F, measured at Fortaleza (3.9° S, 38.4° W) in 2004, all located in the near equatorial region. Wavelet analysis of these time series reveals that there are 3?4-day, 6?8-day and 12?16-day oscillations in the zonal winds and h'F. The 3?4 day oscillation appeared as a form of a wave packet from 7?17 August 2004. From the wave characteristics analyzed this might be a 3.5-day Ultra Fast Kelvin wave. The 6-day oscillation in the mesosphere was prominent during the period of August to November. In the ionosphere, however, it was apparent only in November. Spectral analysis suggests that this might be a 6.5-day wave previously identified. The 3.5-day and 6.5-day waves in the ionosphere could have important roles in the initiation of equatorial spread F (plasma bubble). These waves might modulate the post-sunset E×B uplifting of the base of the F-layer via the induced lower thermosphere zonal wind and/or the E-region conductivity