Showing papers on "Infestation published in 2008"

Soybean Aphid Feeding Injury and Soybean Yield, Yield Components, and Seed Composition

Abstract: Information that describes soybean aphid (Aphis glycines Matsumura) feeding injury effects on soybean [Glycine max (L.) Merr.] yield and seed composition is needed to develop better management practices for this invasive pest. This 2-yr controlled-infestation field study measured aphid populations and the effects of those populations on soybean seed yield, yield components (shoot biomass, pods plant -1 , seeds pod -1 , and 100 seed weight), and seed composition (oil and protein concentrations) when infested at the vegetative (V5) or reproductive (R2) development stages. In 2003, initial infestation rates of 10, 50, or 100 aphids plant -1 applied at V5 resulted in population peaks of 21,000, 18,000, and 12,000 aphids plant -1 and maximum cumulative aphid-days of 381,000, 327,000, and 242,000, respectively. In 2004, initial infestation rates of 1, 3, 10, 50, or 100 aphids plant -1 applied at V5 resulted in population peaks of 4,600, 9,400, 14,000, 22,000, and 21,000 aphids plant -1 and maximum cumulative aphid-days of 101,000, 229,000, 355,000, 514,000, and 537,000. In both years, the same infestation rates applied at R2 resulted in population peaks and cumulative aphid-day values that were about 42 to 88% lower than the V5 infestation dates. Seed yield, yield components, and seed oil concentration declined linearly as peak aphid numbers plant -1 and maximum cumulative aphid-days plant -1 increased. In contrast, seed protein concentration increased linearly with increasing peak aphid numbers plant -1 . Relating these aphid population parameters at the plant growth stages studied enables producers to make informed decisions about the need for and timing of pest management treatments.

A study of the mallophaga of birds with particular reference to their ecology

Abstract: SUMMARY Over three thousand live birds have been examined in the British Isles and Sweden in a study of the ecology and biology of their ectoparasites. The main emphasis has been placed on Mallophaga, which are discussed in this paper. The very exact food and temperature requirements of feather lice are considered. The effect of lice on the host is discussed. Sick or injured birds which are unable to rid themselves easily of parasites tend to develop heavy infestations. The relationship between host and parasite is described. The infestation of five common bird species is analysed on a specific and monthly basis. The proportion of birds carrying various species of lice varies from species to species and from month to month and also between sexes. There is a peak of infestation prior to the bird's breeding season. Rates of infestation on autumn migrants in Sweden are discussed. Birds found uninfested and later found to be infested appear to acquire a parasite population at any season of the year. The habitat of Mallophaga on their hosts is given for each species examined at Silwood Park, Berkshire. The following points are discussed in appendices:–the collection and examination of birds, and an attempt to develop a satisfactory technique for sampling Mallophaga populations.

Infestation of trees by lianas in a tropical forest in Amazonian Peru

Abstract: Question: In Amazonian moist forest, four questions arose: 1. Do tree species differ in their susceptibility to lianas? 2. What host tree traits (branch-free bole height, growth rate, bark type, leaf length and adult stature) are correlated with the susceptibility of tree species to lianas infesting the trunk and the crown? 3. To what extent do spatial variables (proximity to liana-infested trees and the light environment of the tree crown) affect the likelihood of liana infestation? 4. Are spatial variables or tree traits relatively more important in influencing the susceptibility of trees to lianas? We address all questions separately for trunk and crown infestation. Location: Tambopata Nature Reserve, Peru. Methods: We collected information on liana infestation, tree morphological traits, growth, light-environment and position for 3675 trees in seven 1-ha permanent sample plots. We separated trunk from crown infestation and used correlation and logistic regression analyses for tree species and...

Epidemiological aspects of Pediculosis capitis and treatment evaluation in primary-school children in Iran.

Abstract: This study was undertaken to assess the prevalence of and epidemiological factors associated with, head lice infections in Iranian primary schools in 2006 and evaluate data on the therapeutic efficacy of lindane shampoo. A total of 40586 children (19774 boys (48.72%) and 20812 girls (51.28%)] from 198 Governmentprimary schools in Kerman, were screened for head lice between March and June 2006. The diagnosis of head lice infestation was confirmed by clinical inspection of scalp and hair for the presence of adult lice nymphal stage, or eggs (nit) by line-toothed head lice comb. All children infested with lice were treated with lindane shampoo (1% gamma benzene hexachloride). The overall prevalence of head lice infestation was 1.8%. The prevalence of infestation was significantly higher in girls (2.9%) than in boys (0.6%) (p = 0.000). The infestation rate was greater among pupils who were living in rural areas (4.6%) than in urban areas (1.5%). Of the 721 children with a positive examination result, 424 pupils (58.8%) were reported as having been infested with head lice in the previous 6 months. Mother's education level was a significant risk factor in this model (p < 0.05). At 2 weeks after the primary treatment, the success rates of treatment were 49%. Comprehensive survey in our work showed the better future of the disease and related factors. Education campaigns by health care officials, physicians and teachers are expected to be helpful for head lice control. It is essential that governments should be supported form cooperation between the school authorities and public health centers to successful control head lice infestation in primary school. Also there is an urgent need to identify safe, novel insecticides for proved efficacy.

Point prevalence of hard ticks (Ixodids) infesting domestic ruminants of lower Punjab, Pakistan

Abstract: The objective of this study was to determine the diversity and intensity of tick population infesting domestic ruminants in Districts Layyah and Muzaffargarh of lower Punjab (Pakistan). A total of 1050 cattle, 700 buffaloes, 1400 each of sheep and goats and 250 camels were randomly selected and examined for the prevalence of tick infestation. The highest (P=0.00) prevalence of tick infestation was found in cattle (n=789/1050; 75.1%) followed in order by goat (n=723/1400; 51.6%) and buffaloes (n=281/700; 40.08%). None of the examined camels and sheep was found infested with ticks. Hyalomma anatolicum was the most abundant followed by Rhipicephalus sanguineus. Appropriate control measures for ticks need to be employed in the study area for economical animal production.

Investigations on the biology, epidemiology, pathology, and control of Tunga penetrans in Brazil: VII. The importance of animal reservoirs for human infestation.

Abstract: In Brazil tungiasis is endemic in many resource-poor communities, where various domestic and sylvatic animals act as reservoirs for this zoonosis. To determine the role of animal reservoirs in human tungiasis, a cross-sectional study was performed in a traditional fishing community in northeast Brazil. The human and the animal populations were examined for the presence of embedded sand fleas and the prevalence and the intensity of infestation were correlated. The overall prevalence of tungiasis in humans was 39% (95% CI 34-43%). Of six mammal species present in the village, only cats and dogs were found infested. The prevalence in these animals was 59% (95% CI 50-68%). In households, where infested pet animals were present, a higher percentage of household members had tungiasis (42% [95% CI 30-53%] versus 27% [20-33%], p=0.02), and the intensity of the infestation was higher (six lesions versus two lesions, p=0.01). The intensity of infestation in animals correlated with the intensity of infestation in humans (rho=0.3, p=0.02). Living in a household with an infested dog or cat led to a 1.6-fold (95% CI 1.1-2.3, p=0.015) increase in the odds for the presence of tungiasis in household members in the bivariate analysis and remained a significant risk factor in the multivariate regression analysis. The study shows that in this impoverished community tungiasis is highly prevalent in humans and domestic animals. In particular, it underlines the importance to include animals in control operation aiming at the reduction of disease occurrence in the human population.

Attributes associated with probability of infestation by the pinon Ips, Ips confusus, (Coleoptera: Scolytidae) in pinon pine, Pinus edulis

Abstract: (Please note, this is an abstract only) We examined attributes associated with the probability of infestation by pinon ips (Ips confusus), in pinon pine (Pinus edulis), in an outbreak in the Coconino National Forest, Arizona. We used data collected from 87 plots, 59 infested and 28 uninfested, and a logistic regression approach to estimate the probability of infestation based on plot- and tree-level attributes. Pinon pine stand density index was a good predictor of the likelihood of infestation by pinon ips at the plot level and a cross-validation analysis indicated that the model correctly classified 82% of the cases. Diameter at root collar and pinon dwarf mistletoe infestation level were good predictors of individual tree infestation and a cross-validation analysis indicated that the model correctly classified 72% of the cases. Results suggest that the occurrence of pinon ips infestations may be related to stress factors associated with increased stocking and pinon dwarf mistletoe infestations.

Carrapatos do gênero amblyomma (acari: ixodidae) e suas relações com os hospedeiros em área endêmica para febre maculosa no Estado de São Paulo

Abstract: Seven species of mammals and 36 of birds were investigated to determine the tick prevalence and intensity of infestation. The study was conducted at the Esalq/USP in Piracicaba municipality, State of Sao Paulo. It was collected 52 mammals and 158 birds parasitized by 12,418 ticks. Adult ticks (N= 7,343) were found on capybaras, while the immature were mainly collected on small mammals and birds. The main hosts for immatures in descending order were opossums (69.1%), capybara (24.4%) and black vultures (3.7%). Among the avifauna, the black vulture (Cathartidae) had the heaviest infestation (69.9%) followed by species of the Thamnophilidae and Turdidae families. Adult ticks collected on capybaras were A. cajennense (80.8%) and A. dubitatum (19.2%). Both tick species were also found on opossums corresponding to 72.4% and 27.6%, respectively. Due to easy capture and attractiveness for ticks, opossums could be used as bioindicators in Brazilian zoonotic areas with spotted fever. Considering the prevalence and also abundance of ticks, host attractiveness, proliferation and susceptibly for R. rickettsi infection, capybaras and opossums are the main amplifying hosts for this microorganism at the ESALQ/Campus, while horses, black vultures and stray cats act as secondary hosts.

Head lice infestation in school children of a low socio- economy area of Tabriz city, Iran

Abstract: Head lice infestation (HLI) caused by Pediculus humanus var capitis (Pediculus capitis) is a world wild public health concern that affects mostly school aged children. HLI does not produce an illness, but it is physically unpleasant and an unbearable social stigma. Over a five months period from July to November, 2006, 2795 school children from a low socio-economy area of Tabriz city enrolled in 13 elementary and high schools (governmental school) including 1948 girls (69.69 %) and 847 boys (30.30%) were examined for the presence of Pediculus capitis (nits, adults and immature). During this study all the infested cases were seen among girls and there was no infestation in boys. School girls aged 10-14 years constituted the highest infestation rate (6.5%) and the lowest infestation rate was seen in girls aged 15-18 years old (1.6%). The infestation rate in 5-9 years old children was 5.7%. The overall infestation rate in the studied population was 3.64%. There was a significant difference between infestation rates among the age groups X 2 = 15.43, df = 2, p = 0.0004). But there was no significant difference between the infestation rates of 5-9 and 10-14 groups(X 2 =0.36, df=1, p=0.55). Pediculosis is a public health issue in many parts of the world. Certainly, personal hygiene practices and socioeconomic status influence the level of prevalence of pediculosis. The lowest infestation rate in 15-18 years old children in this study may indicates that the better personal hygiene practices including regular combing and washing of the hair is the main reason for reducing the head lice infestation rate in this group in comparison with the two other groups. The overall infestation rate in the present study is probably one of the lowest infestation rates in Iran and in the region.

Detection and Investigation of Soil Biological Activity against Meloidogyne incognita

Abstract: Greenhouse experiments with two susceptible hosts of Meloidogyne incognita, a dwarf tomato and wheat, led to the identification of a soil in which the root-knot nematode population was reduced 5- to 16-fold compared to identical but pasteurized soil two months after infestation with 280 M. incognita J2/100 cm3 soil. This suppressive soil was subjected to various temperature, fumigation and dilution treatments, planted with tomato, and infested with 1,000 eggs of M. incognita/100 cm3 soil. Eight weeks after nematode infestation, distinct differences in nematode population densities were observed among the soil treatments, suggesting the suppressiveness had a biological nature. A fungal rRNA gene analysis (OFRG) performed on M. incognita egg masses collected at the end of the greenhouse experiments identified 11 fungal phylotypes, several of which exhibited associations with one or more of the nematode population density measurements (egg masses, eggs or J2). The phylotype containing rRNA genes with high sequence identity to Pochonia chlamydosporia exhibited the strongest negative associations. The negative correlation between the densities of the P. chlamydosporia genes and the nematodes was corroborated by an analysis using a P. chlamydosporia-selective qPCR assay.

Plastic detection comb better than visual screening for diagnosis of head louse infestation.

Abstract: Finding lice can be difficult in head louse infestation. We compared a new louse detection comb with visual inspection. All children in two rural Turkish schools were screened by the two methods. Those with lice were offered treatment and the results monitored by detection combing. Children with nits only were re-screened to identify latent infestations. Using visual inspection we found 214/461 children (46%) with nits but only 30 (6.5%) with live lice. In contrast detection combing found 96 (21%) with live lice, of whom 20 had no nits. Detection combing was 3.84 times more effective than visual inspection for finding live lice. Only 10/138 (7.2%) children with nits and no lice were found to have active infestation by day 16. We found that the detection comb is significantly (P<0.001) more effective than visual screening for diagnosis; that nits are not a good indicator of active infestation; and that treatment with 1% permethrin was 89.6% effective.

Changes in epidemiological patterns of sea lice infestation on farmed Atlantic salmon, Salmo salar L., in Scotland between 1996 and 2006.

Abstract: Analyses of a unique database containing sea lice records over an 11 year period provide evidence of changing infestation patterns in Scotland. The data, collected from more than 50 commercial Atlantic salmon farms, indicate that both species of sea lice commonly found in Scotland, Lepeophtheirus salmonis and Caligus elongatus, have declined on farms over the past decade. Reductions for both species have been particularly marked since 2001 when more effective veterinary medicines became available. Treatment data were also available in the database and these show a growing trend towards the use of the in feed medication emamectin benzoate (Slice), particularly in the first year of the salmon production cycle. However, this trend to wards single product use has not been sustained in 2006, the latest year for which data are available. There is some evidence of region to region variation within Scotland with the Western Isles experiencing higher levels of infestation. However, compared to the levels observed between 1996 and 2000, all regions have benefited from reduced lice infestation, with the overall pattern showing a particular reduction in the second and third quarters of the second year of production.

Eficiência in vitro de acaricidas sobre carrapatos de bovinos no Estado do Rio Grande do Sul, Brasil

Abstract: Infestation by ticks is responsible for significant economic losses to the cattle industry in several regions, including Rio Grande do Sul (RS) state. Losses may be derived from animal stress, weight loss and skin damage, as well as from costs with treatment. The indiscriminated use of pesticides against these parasites has resulted in high levels of genetic resistance to several drugs, representing a problem for disease control. Thus, the objective of this research was to evaluate the susceptibility of field specimens of Rhipcephalus (Boophilus) microplus to the acaricides used in the control of the parasite. Female ticks obtained from 42 farms in different counties of RS were submitted to the engorgeted female immersion test, to estimate the resistance of the parasite to the drugs. Amitraz in combination with chlorpyriphos was the most efficient drug, acting effectively in ticks from 100% of the tested farms (11/11). Associations of cypermethrin-chlorpyriphos-citronelol were efficient in ticks from 61% of the farms (25/41) and cypermethrin-ethion in 37% (10/27). Cypermethrin alone was efficient in 20,7% (6/29) and Amitraz. one of the most used products, was efficient in ticks from only 14,2% (6/42) of the farms. These results demonstrate that most drugs used in the control of R. B. microplus in the state present low efficacy, as measured by in vitro tests. The low drug efficacy is probably derived from the genetic resistance developed by the parasites due to the indiscriminated and inadequate use of these acaricides in the field.

Prevalence and risk factors of hookworm-related cutaneous larva migrans in a rural community in Brazil.

Abstract: The epidemiology of hookworm-related cutaneous larva migrans (HrCLM) in endemic communities is not well understood. To describe the prevalence of HrCLM and to identify environmental and behavioural risk factors for the infestation, two cross-sectional surveys were conducted in a small village in an endemic area of north–eastern Brazil — one in the rainy season and the other in the dry season. The members of each household were examined clinically for the presence of HrCLM, and information on possible risk factors was collected. HrCLM, which was diagnosed in 45 individuals in the rainy-season survey and in 17 in the dry-season survey, was significantly more prevalent in the rainy season (4.4% v. 1.7%; P<0.001). The age-specific prevalences peaked, at 14.9%, in infants and children aged ≤ 4 years.In a logistic regression analysis, the independent risk factors for current infestation or infestation in the preceding 6 months were identified as young age (odds ratio = 0.96; 95% confidence interval = 0....

Tick infestation risk and Borrelia burgdorferi s.l. infection-induced increase in host-finding efficacy of female Ixodes ricinus under natural conditions

Abstract: An investigation of the risk of human tick infestation, together with the prevalence of Borrelia burgdorferi s.l. infection, was conducted in a sylvatic habitat in western Germany to provide data needed for future risk-benefit evaluations of acaricides used for clothing impregnation. Additionally, data were collected on behavioural changes in Borrelia burgdorferi s.l.-infected adult female I. ricinus ticks and the possible impact of such changes on host-finding efficacy. The risk of I. ricinus-infestation was determined by collecting from the protective clothing of volunteers and by dragging in known tick-infested sites in the Kuhkopf Mountain area, Koblenz, Germany, from June through October 2006. The overall tick infestation rate per person per hour was 7.4 ± 5.5, with the following sex- and stage-specific differences: males 0.32 ± 0.37, females 1.1 ± 1.2, nymphs 3.6 ± 4.4, larvae 2.4 ± 3.5. Concurrent dragging revealed an average 19.4 ± 16.2 times higher infestation rate as well as a markedly lower infection rate with borreliae in adult I. ricinus ticks when compared to ticks collected from exposed human volunteers. Although the difference in infection rates was statistically significant (P < 0.023) only in adult female ticks, our data indicate that B. burgdorferi s.l. infection may increase host-finding efficacy in adult I. ricinus. The overall exposure risk was 1.0 B. burgdorferi s.l.-infected ticks per person per hour of exposure, or 0.25 ticks per 100 m walking distance in the study area.

Influence of Mahanarva fimbriolata (Stål) (Hemiptera: Cercopidae) injury on the quality of cane juice

Abstract: Mahanarva fimbriolata (Stal) is an important pest in Latin America and causes significant reduction in sugarcane productivity. There is no information regarding the effect of this pest on the quality of cane juice used for sugar and alcohol production. This work aimed at evaluating the quality of sugarcane juice from plants attacked by spittlebugs. The experiment was arranged in a completely randomized design with 15 replications, and comprised two treatments: control and chemical treatment with thiamethoxam. An average of 9.2 +/- 4.44 spittlebug nymphs m-1 were found in the plots prior to insecticide application. Nymphs were counted 18, 35, 55, and 82 days after the initial sampling (december/2003). During the mid growing season (July 2004), the juice was extracted from stalks and analyzed for Brix, Pol, RS, pH, fiber, purity, TRS, dextran, starch, and total phenolic compounds. Stalk yield was also measured. Chemical treatment was efficient in reducing spittlebug population, and elevated both stalk yield and juice pH. The accumulated infestation expressed as insect-days was significantly and negatively correlated to yield, Pol, pH, and purity. The concentration of phenolic compounds increased with pest infestation, while dextran and starch levels were not affected. The infestation of 2.4 and 7.3 nymphs m-1 day-1 caused reductions of 8.3% and 29.8% in yield; 1.9% and 5.8% in Pol; 0.4% and 1.1% in pH and 0.4% and 1.2% in purity, respectively, in comparison to areas where the pest population was extremely low (< 0.1 nymphs m-1).

Influence of canopy aspect and height on codling moth (Lepidoptera: Tortricidae) larval infestation in apple, and relationship between infestation and fruit size.

Abstract: Monitoring systems based on traps with female attractants are expected to enhance forecasting of insect population size and damage. The optimal placement of such traps should match the small-scale distribution of ovipositing females. In the codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), fruit infestation takes place in proximity to the oviposition site. We characterized the within-tree distribution of codling moth infestations and the size of uninfested fruit based on a survey of 40,000 apples (Malus spp.) from trees belonging to 160 different apple genotypes and growing in two different environments. Each tree was subdivided into 12 sectors, considering canopy aspect (north, east, south, and west) and canopy height (bottom, middle, and top). This study revealed that fruit infestation by the first but not by the second generation of larvae correlated significantly with canopy aspect. Similarly, fruit size differed significantly between the north- and the south-facing tree side for the period of infestation by the first but not by the second larval generation. Significantly lower fruit infestation was observed on the north- compared with the south- or east-facing tree side for the first generation. A significant influence of canopy height on larval infestation was observed in three of eight assessments, in which the middle height level showed the highest infestations. Significant differences in within-tree distribution of codling moth infestation suggest that oviposition preference is guided by nonrandom factors including microclimate, fruit phenology, and wind direction. These cultivar-independent findings should be considered in future monitoring systems that focus on female codling moth.

Field performance of improved cowpea varieties under conditions of natural infestation by the parasitic weed Striga gesnerioides

Abstract: Cowpea is an important food crop in the dry savannas of West and Central Africa because of its high protein content. Yields are, however, considerably reduced by the parasitic angiosperm Striga gesnerioides. Field trials over 2 years in two localities in northeast Nigeria evaluated the performance of diverse cowpea varieties under conditions of natural infestation by Striga. Grain yield was higher in Tilla than in Damboa where the higher Striga infestation may be caused by the lower rainfall and the sandy nature of the soils. Two varieties (IT97K-499-35 and IT90K-82-2) were confirmed to be resistant to Striga. Yield gain from IT97K-499-35 over the local variety ranged from 30% in Tilla in the northern Guinea savanna to 126% in Damboa in the Sudan savanna. The local variety Borno Brown and two improved varieties were found to be as susceptible to Striga as the susceptible control, TVX-3236, and therefore may not be recommended for cultivation in areas where Striga infestation is a problem. One variety, rep...

Fungal Diversity of Norway Spruce Litter: Effects of Site Conditions and Premature Leaf Fall Caused By Bark Beetle Outbreak

Abstract: Fungi play an important role in leaf litter decomposition due to their ability to break down the lignocellulose matrix, which other organisms are unable to digest. However, little is known regarding the factors affecting components of fungal diversity. Here, we quantified richness of internal fungi in relation to litter nutrient and phenolic concentrations, sampling season (spring or fall), and premature leaf shedding due to low precipitation and infestation of bark beetles (mainly Ips typographus and Ips duplicatus). The study was conducted in 37-year-old Norway spruce [Picea abies (L.) Karst.] stands, with three plots each in mixed forest (MF) and coniferous forest (CF) site conditions in south-central Poland. Fifty-four species of sporulating fungi were identified in 2,330 freshly fallen needles sampled during 2003-2005, including 45 species in MF and 31 in CF. The significantly higher number of species in MF was likely related to moister conditions at that site. Among isolated fungi, 22% (12 species) were identified as endophytes of Norway spruce in prior studies. During spring of 2005, we found less than half the number of isolates and fungal species at each forest site as compared to fall for the two prior years. This pattern was observed in typical soil fungi (e.g., Penicillium daleae, Penicillium purpurogenum) and endophytes/epiphytes (e.g., Aureobasidium pullulans, Alternaria alternata, Cladosporium spp., and Lophodermium piceae). Premature shedding of needles was the most likely cause of this decline because it shortened the time period for fungi to infect green needles while on the tree. For all sites and sampling periods, richness of internal fungi was strongly and positively related to the age of freshly fallen litter (assessed using needle Ca concentration as a needle age tracer) and was also negatively related to litter phenolic concentration. Richness of internal fungi in freshly fallen litter may be adversely affected by low soil moisture status, natural inhibitors slowing fungal colonization (e.g., phenolics) and biotic (e.g., insect infestation) and abiotic (e.g., drought) factors that shorten leaf life span.

Seasonal Frequency of Ectoparasite Infestation in Dogs from Shiraz, Southern Iran

Abstract: The objective of this study was to determine the prevalence of canine ectoparasite infestation in pet dogs from the Shiraz area of southern Iran, with no known exposure to insecticides. In all, 160 dogs were examined for ectoparasites in each of the 4 seasons and samples were collected. The most common ectoparasite was Ctenocephalides canis, which infested 22 of the 160 dogs. Pulex irritans was identified on 2 of the dogs and 142 Rhipicephalus sanguineus ticks were found on 13 dogs. Trichodectes canis was observed on 2 dogs and 8 dogs had Hippobosca flies, which were seen mostly in spring. All superficial skin scrapes for mite detection were negative. A significant correlation was observed between increases in temperature and decreases in humidity, and increased ectoparasite infestation (r = 0.26; P = 0.001 and r = 0.23; P = 0.004, respectively). The number of dogs infested with ectoparasites in summer and spring was significantly higher than in winter (P = 0.007).

Intestinal helminth infestation is associated with increased bronchial responsiveness in children.

Abstract: Non-atopic asthma is the predominant phenotype in non-affluent parts of Latin America. We recently reported that infestation with Ascaris lumbricoides increased the risk of non-atopic asthma in less affluent areas of Brazil but the mechanism is unclear. The present study was conducted to determine whether helminth infestation is associated with heightened bronchial responsiveness (BHR), a common finding in asthma. A random sample of 50 asthmatic and 50 non-asthmatic controls (mean age 10.1 years) were selected from a larger cohort (n = 1,011) without knowledge of their helminth infestation status. Three stool samples were collected from each child on different days and each sample was analyzed by the Kato-Katz method for quantitative determination of helminth eggs. Bronchial provocation tests were performed with inhaled 4.5% hypertonic saline using the ISAAC Phase II standardized protocol. There was no difference between the prevalence of positive BHR in the asthmatics (20.4%) compared with the controls (14.6%) (P = 1.0). Helminth infestation was detected in 24.0% of children, with A. lumbricoides being the most common. Children with high load infestation (>or=100 eggs/g) were five times more likely to have BHR than children with low load or no infestation. Despite the small sample size the results of the present study suggest that the link between high load helminth infestation and non-atopic asthma may be mediated via heightened bronchial responsiveness, possibly due to an inflammatory response to the pulmonary phase of the helminth life cycle.

Determination of host status of citrus fruits against the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae)

Abstract: The Mediterranean fruit fly (Medfly), Ceratitis capitata (Wiedemann) is a pest of citrus in parts of Western Australia. Three citrus cultivars: Valencia oranges, Eureka lemons and Imperial mandarins, as well as non-citrus control fruits, were examined for attractiveness and suitability to Medfly in the field and in the laboratory using choice and no-choice experiments. Oranges were more susceptible to Medfly than mandarins and lemons. Punctures in the skin had a significant impact on the degree of infestation in both citrus and non-citrus control fruit. Artificial infestation and larval survivorship were used to investigate the suitability of each cultivar to Medfly under laboratory conditions. Oranges and mandarins were suitable for the development of Medfly, but lemons were a poor host. When each cultivar was in season, field cage trials demonstrated that infestation occurred in oranges and mandarins but not in lemons.