Ecological control of Triatoma dimidiata (Latreille, 1811): five years after a Costa Rican pilot project

An ecological pilot project for the control of Triatoma dimidiata allowed a new evaluation four and five years after environmental modifications in the peridomestic areas of 20 households. It was verified that the two groups of houses, 10 case-houses and 10 control-houses, were free of insects after those periods of time. In the first group, the owners started a chicken coop in the backyard and a colony of bugs was found there without infesting the house. In the second group, the inhabitants of one house once again facilitated the conditions for the bugs to thrive in the same store room, reaffirming that man-made ecotopes facilitates colonization. This ecological control method was revealed to be reliable and sustainable and it is recommended to be applied to those situations where the vectors of Chagas disease can colonize houses and are frequent in wild ecotopes.     

Cleptohaematophagy of the Triatomine bug Belminus herreri

The Triatomine bug Belminus herreri, previously known only from Panama, is reported for the first time from Colombia. Three adult B. herreri were collected from a chicken coop and a viable egg was found on a Bactris palm at Carmen municipality in humid forest zone at 680 m altitude. From 44 eggs produced, five progeny were reared to adulthood. During early instars they were unable to take bloodmeals directly from vertebrate hosts, but they fed successfully by cleptohaematophagy on blood from replete Rhodnius prolixus.     

Peridomestic natural breeding sites of Nyssomyia whitmani (Antunes and Coutinho) in an endemic area of tegumentary leishmaniasis in northeastern Argentina

The scarce information about breeding sites of phlebotomines limits our understanding of the epidemiology of tegumentary leishmaniasis. Identifying the breeding sites and seasons of immature stages of these vectors is essential to propose prevention and control strategies different from those targeting the adult stage. Here we identified the rural breeding environments of immature stages of Ny. whitmani, vector species of Leishmania braziliensis in the north of Misiones province, Argentina; then we determined and compared the environmental and structural characteristics of those sites. We also identified the season of greatest emergence and its relationship with adult abundance. During a first collection period, between 28 and 48 emergence traps were set continuously for 16 months in six environments of the farm peridomicile and domicile: below house, chicken shed, experimental chicken shed, forest edge, pigsty and under fruit tree. Traps were checked and rotated every 40 nights. A total of 146 newly emerged individuals were collected (93.8% of them were Ny. whitmani), totaling an effort of 23,040 emergence trap-nights. The most productive environments were chicken shed and below house, and the greatest emergence was recorded in spring and summer. During a second collection period, emergence traps and light traps for adult capture were placed in the chicken shed and below house environments of eight farms. Emergence traps were active continuously during spring, summer, and early autumn. Environmental and structural characteristics of each environment were recorded. A total of 84 newly emerged phlebotomines (92.9% Ny. whitmani; 72,144 emergence trap-nights) and 13,993 adult phlebotomines (147 light trap-nights) were recorded in the chicken shed and below house environments. A positive correlation was also observed between trap success of newly emerged phlebotomines and of adults after 120 days. A high spatial variability was observed in the emergence of Ny. whitmani, with the number of newly emerged individuals being highest in soils of chicken sheds with the highest number of chickens and closest to forest edge. Moreover, below house was found to be as important as chicken sheds as breeding sites of Ny. whitmani. Management of the number of chickens in sheds, soil moisture and pH, and the decision of where to localize the chicken sheds in relation to the houses and the forest edge, might contribute to reduce the risk of human vector exposure and transmission of Leishmania.     

家蝇作为饲料添加剂对清远良种鸡肉质和风味的影响

测定蝇蛆和蝇蛹作为饲料添加剂对清远良种鸡肉质和风味的影响,为家蝇Musca domestica L.作为添加饲料改善鸡的肉质和风味,以及代替鱼粉成为新的蛋白质来源提供数据。150只清远鸡雏鸡随机等分成5组,以鱼粉或商业饲料加入不同比例的家蝇幼虫或蝇蛹作为添加饲料加以饲养。结果显示,饲喂不同食料的清远鸡的增重、脾重和法氏囊重影响差异不显著,但饲喂蝇蛆和蝇蛹的鸡群的死亡率明显低于仅饲喂鱼粉或商业饲料的鸡群;饲喂蝇蛆或蝇蛹的鸡肉的系水力(用失水率表示)和风味评价明显提高,氨基酸含量差异显著。说明家蝇幼虫作为动物蛋白可提高鸡的抗疾病能力及改善鸡肉风味。     

Detection and source identification of airborne extended-spectrum beta-lactamase-producing Escherichia coli isolates in a chicken house

To identify airborne dissemination of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli (E. coli) in a chicken house, airborne E. coli was collected from indoor air of a chicken house using six-stage Anderson sampler, and E. coli from chicken fecal samples were also isolated simultaneously. ESBL-producing E. coli isolates from indoor air and fecal samples were screened by a phenotypic confirmatory test according to CLSI recommendations. And then, the enterobacterial repetitive intergenic consensus polymerase chain reaction was performed to analyze the source of airborne ESBL-producing E. coli. The results showed that the ESBL-positive rates of E. coli isolates from feces and the indoor air were 56 % (18/32) and 40 % (6/15), respectively. Furthermore, airborne ESBL-producing E. coli isolates in the chicken house had 100 % genetic similarities with the strains from chicken feces, indicating that ESBL-producing E. coli from chicken feces could be aerosolized and spread to the air.     

Risk factors and reproductive disorders associated with canine herpesvirus-1 (CHV-1)

Canine herpesvirus-1 (CHV-1) is presumed to be enzootic in the dog population and is associated with fertility disorders and neonatal mortality. In this study we screened for risk factors affecting CHV-1 antibody titers and investigated the association between antibody titers and reproductive disorders. Therefore, serum from 545 dogs used for reproduction was analysed with an ELISA. Using a forward stepwise procedure and retaining significant risk factors (P<0.05), best fitting multifactorial generalized linear model (glm) procedures were built for males and females. The effect of antibody titers on reproductive disorders was analysed with logistic regression analysis. The association between reproductive disorders and seroprevalence was analysed in chi-square analyses using contingency tables. In both sexes, kennel cough and breeding management were found to have an impact on the CHV-1 antibody titer. Also, the influence of kennel cough on the antibody titer was correlated to the hygienic status of the kennel. In females, age, kennel size and cycle stage had an effect on CHV-1 antibody titers. Furthermore, kennel size and hygiene were found to be correlated. In males, mating experience had an impact on CHV-1 antibody titers. An association was observed between serological status and a history of abortion in bitches. In conclusion, this study suggests CHV-1 antibody titers may be affected by many factors, both on an environmental and host level. Therefore, interpretation of the serological status requires precaution. Furthermore, oronasal and venereal transmission seem to play a role in the spreading of infection.     

Species specificity and developmental patterns of expression of the beta amyloid precursor protein (APP) gene in brain, liver and choroid plexus in birds.

1. Human APP cDNA hybridized to a 3.5 kb mRNA in liver and brain RNA from chickens, pigeons, quail and ducks as well as in RNA from choroid plexus of chicken and quail. In contrast to all other species hitherto examined a 1.6 kb mRNA hybridizing to APP cDNA was found in abundant amounts in RNA from chicken and quail livers. 2. In the chicken, before hatching, the levels of APP mRNA in total RNA from liver and choroid plexus were higher than those in RNA from liver and choroid plexus of adults. However, RNA from the rest of the brain of chicken embryos contained less APP mRNA than RNA from brain of adults. 3. In the chicken, between 10 and 40 days after hatching, APP mRNA levels in RNA from liver were higher than adult levels, APP mRNA levels in RNA from choroid plexus were similar to adult levels and APP mRNA levels in RNA from the rest of brain were below the adult levels.     

Subtyping Salmonella enterica serovar enteritidis isolates from different sources by using sequence typing based on virulence genes and clustered regularly interspaced short palindromic repeats (CRISPRs)

Salmonella enterica subsp. enterica serovar Enteritidis is a major cause of food-borne salmonellosis in the United States. Two major food vehicles for S. Enteritidis are contaminated eggs and chicken meat. Improved subtyping methods are needed to accurately track specific strains of S. Enteritidis related to human salmonellosis throughout the chicken and egg food system. A sequence typing scheme based on virulence genes (fimH and sseL) and clustered regularly interspaced short palindromic repeats (CRISPRs)-CRISPR-including multi-virulence-locus sequence typing (designated CRISPR-MVLST)-was used to characterize 35 human clinical isolates, 46 chicken isolates, 24 egg isolates, and 63 hen house environment isolates of S. Enteritidis. A total of 27 sequence types (STs) were identified among the 167 isolates. CRISPR-MVLST identified three persistent and predominate STs circulating among U.S. human clinical isolates and chicken, egg, and hen house environmental isolates in Pennsylvania, and an ST that was found only in eggs and humans. It also identified a potential environment-specific sequence type. Moreover, cluster analysis based on fimH and sseL identified a number of clusters, of which several were found in more than one outbreak, as well as 11 singletons. Further research is needed to determine if CRISPR-MVLST might help identify the ecological origins of S. Enteritidis strains that contaminate chickens and eggs.     

Detection of methane and quantification of methanogenic archaea in faeces from young broiler chickens using real-time PCR

AIMS: To detect the presence of methanogens in the faeces of broiler chicks during the first 2 weeks of age. METHODS AND RESULTS: Chicken faecal samples from 120 broiler chicks were incubated for methane gas formation and methanogenic archaea were analysed using real-time PCR. The copy number of the order Methanobacteriales 16S rDNA gene in chicken faeces when the broilers were 3-12 days of age, litter and house flies collected in the bird house ranged from 4.19 to 5.51 log(10) g(-1) wet weight. The number of positive methane culture tubes increased from 25% to 100% as the birds aged. CONCLUSIONS: Methanogens were successfully detected in faecal samples from 3- to 12-day-old broilers, as well as litter and house flies using real-time PCR. The copy number of methanogenic 16S rDNA gene in these samples was also similar to the number observed in litter and house flies. SIGNIFICANCE AND IMPACT OF THE STUDY: The same methanogens consistently appeared in chicken faeces a few days after birth. Detection of the methanogenic bacteria in litter and house flies implicated them as potential environmental sources for methanogen colonization in broiler chicks.     

Origins of H-2 polymorphism in the house mouse. II. characterization of a model population and evidence for heterozygous advantage

Comparison of the rate of synonymous and nonsynonymous nucleotide substitutions suggests that certain regions of the functional H-2 genes, which are part of the mouse major histocompatibility complex (Mhc), are under strong positive selection pressure. Thus far, however, little evidence has been provided for the existence of such pressure in natural mouse populations. We have, therefore, initiated experiments designed to test the hypothesis of positive selection acting on H-2 loci. The experiments are being carried out on two natural mouse populations in Jerusalem, Israel. One population occupies a space of about 100 m² in a chicken coop, the other lives in a nearby field in which mouse stations providing food and shelter have been set up. Extensive typing of these two populations revealed the presence of only four H-2 haplotypes. Mice in the two populations breed continually all year around, yet population size varies seasonally, with population maxima in winter and minima in summer. The population in the chicken coop contains a relatively stable nucleus which may be organized in demes with an excess of females over males and limited territorial mobility. The rest of the mice stay in the population for a short time only and then either die or emigrate. The field population is smaller and more loosely organized than the chicken-coop population, with demes probably forming only during population maxima. For the rest of the time breeding in this population is probably panmictic. At a population minimum in the summer of 1984, H-2 homozygotes happened to predominate over heterozygotes. This situation, however, lasted for a short time only and thereafter there was a continuous, statistically highly significant increase in the proportion of H-2 heterozygotes of one or two types. The increase occurred in both populations but was more apparent in the chicken-coop population. This observation provides the first experimental evidence that heterozygous advantage might be one of the mechanisms maintaining high H-2 polymorphism in natural populations of the house mouse.     

Comparison of bacterial diversity in wheat bran and in the gut of larvae and newly emerged adult of Musca domestica (Diptera: Muscidae) by use of ethidium monoazide reveals bacterial colonization

The objective of the current study is to investigate the bacterial colonization within the gut of the house fly, Musca domestica L. (Diptera: Muscidae), at the larval stage and the bacterial community of the gut of the house fly at the newly emerged adult stage. After using ethidium monoazide to inhibit recovery of nucleic acids from dead bacteria, three polymerase chain reaction (PCR)-amplified 16S rDNA libraries from wheat bran, larvae, and newly emerged adults was constructed, analyzed, and compared. In total, 24, 11, and four phylotypes in the 16S rDNA libraries of wheat bran and the gut of larvae and adults, respectively, were found and assigned to three phylogenetic phyla of the domain Bacteria: Firmicutes, Proteobacteria, and Bacteroidetes. In the wheat bran library, 76% of the total number of sequences were affiliated to the genera Pseudomonas, Halomonas, Providencia, and Ignatzschineria. The three genera Morganella (79.05%), Providencia (8.78%), and Ignatzschineria (9.46%) dominated the library of the larval gut. Compared with the wheat bran library, the relative abundance of Morganella morganii (Winslow) was significantly higher (79.05 versus 0.8%), whereas that of Ignatzschineria larvae and of Providencia spp. was similar. These results demonstrate that M. morganii, Providencia spp., and I. larvae colonized the gut of the house fly larvae. Live bacteria of M. morganii, Providencia spp., and Proteus spp. were found in the gut of newly emerged adults. Therefore, the bacteria M. morganii and Providencia spp. colonized the larval gut could survive in the gut from larval metamorphosis to adult eclosion of the house fly.     

Alaskan malamute chondrodysplasia--VII. Isolation and characterization of copper, zinc and iron binding proteins in Canis familiaris.

1. Three low molecular weight (12,000, 10,000 and 7,000) metal binding proteins have been isolated from the livers of normal and chondrodysplastic Alaskan Malamutes. 2. Comparison studies between kennel (mixed breed) dogs and both adult and immature Alaskan Malamutes suggested that the disturbance in trace mineral metabolism found in the Malamutes is almost entirely reflected in the 12,000 mol. wt species. 3. The major copper-inducible protein (10,000 mol. wt) observed in kennel dogs was not found to be inducible in Malamutes and contained constant ratios of both copper and zinc to protein in metal binding proteins isolated from the livers of both normal and dwarf Malamutes. 4. The copper and zinc found in the UM2 concentrates (mol. wt greater than 2000) of immature Malamutes showed very little affinity to the proteins and these metals were found chiefly in a peptide fraction which apparently serves as a reservoir from which the storage proteins obtain the metals that they bind. 5. Regression analysis indicated a statistically significant correlation between both copper and zinc concentrations and the carbohydrate concentration in the proteins investigated.     

Impacts of poultry house environment on poultry litter bacterial community composition

Viral and bacterial pathogens are a significant economic concern to the US broiler industry and the ecological epicenter for poultry pathogens is the mixture of bedding material, chicken excrement and feathers that comprises the litter of a poultry house. This study used high-throughput sequencing to assess the richness and diversity of poultry litter bacterial communities, and to look for connections between these communities and the environmental characteristics of a poultry house including its history of gangrenous dermatitis (GD). Cluster analysis of 16S rRNA gene sequences revealed differences in the distribution of bacterial phylotypes between Wet and Dry litter samples and between houses. Wet litter contained greater diversity with 90% of total bacterial abundance occurring within the top 214 OTU clusters. In contrast, only 50 clusters accounted for 90% of Dry litter bacterial abundance. The sixth largest OTU cluster across all samples classified as an Arcobacter sp., an emerging human pathogen, occurring in only the Wet litter samples of a house with a modern evaporative cooling system. Ironically, the primary pathogenic clostridial and staphylococcal species associated with GD were not found in any house; however, there were thirteen 16S rRNA gene phylotypes of mostly gram-positive phyla that were unique to GD-affected houses and primarily occurred in Wet litter samples. Overall, the poultry house environment appeared to substantially impact the composition of litter bacterial communities and may play a key role in the emergence of food-borne pathogens.     

Alaskan malamute chondrodysplasia--VIII. Incorporation of [14C]glucosamine and [3H]serine in hepatic metal-binding proteins of Canis familaris.

1. Hepatic proteins isolated from control kennel dogs bound small quantities of zinc and iron and the peptide fraction contained neither metal. 2. Zince loading of kennel dogs stimulated an hepatic uptake of five times more zinc and three times more iron than an equivalent copper load. The increase in metal concentration was noted in the 10,000 dalton protein. 3. Both the 12,000 and 10,000 dalton proteins isolated from kennel dogs contained more binding sites specific for zinc than for either copper or iron. All three proteins isolated from Alaskan Malamutes showed a smaller affinity for zinc than copper or iron. 4. Both copper and zinc loading stimulated an uptake of [14C]glucosamine and [3H]serine from the peptide fraction of control kennel dogs into the 10,000 dalton protein.     

Distributions of lesser mealworm (Coleoptera: Tenebrionidae) in litter of a compacted earth floor broiler house in subtropical Queensland, Australia

Distributions of lesser mealworm, Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae), in litter of a compacted earth floor broiler house in southeastern Queensland, Australia, were studied over two flocks. Larvae were the predominant stage recorded. Significantly low densities occurred in open locations and under drinker cups where chickens had complete access, whereas high densities were found under feed pans and along house edges where chicken access was restricted. For each flock, lesser mealworm numbers increased at all locations over the first 14 d, especially under feed pans and along house edges, peaking at approximately 26 d and then declining over the final 28 d. A life stage profile per flock was devised that consisted of the following: beetles emerge from the earth floor at the beginning of each flock, and females lay eggs, producing larvae that peak in numbers at approximately 3 wk; after a further 3 to 4 wk, larvae leave litter to pupate in the earth floor, and beetles then emerge by the end of the flock time. Removing old litter from the brooder section at the end of a flock did not greatly reduce mealworm numbers over the subsequent flock, but it seemed to prevent numbers increasing, while an increase in numbers in the grow-out section was recorded after reusing litter. Areas under feed pans and along house edges accounted for 5% of the total house area, but approximately half the estimated total number of lesser mealworms in the broiler house occurred in these locations. The results of this study will be used to determine optimal deployment of site-specific treatments for lesser mealworm control.     

Avoidance reactions of domestic dogs to unfamiliar male and female humans in a kennel setting

Most kennel owners and veterinarians prefer women assistants because these animalcare professionals assume that women elicit less avoidance from domestic animals than men. To evaluate this assumption, 10 male and 10 female dogs were given two human-reaction tests to assess their behavior in the presence of an unfamiliar man or woman in a commercial kennel setting. Female dogs showed little reluctance to approach and make contact with the unfamiliar human, regardless of the person's gender. In contrast, male dogs were much less likely to approach and make body contact with the unfamiliar man.     

Natural Infections Caused by the Fungus <Emphasis Type="Italic">Beauveria bassiana</Emphasis> as a Pathogen of <Emphasis Type="Italic">Musca domestica</Emphasis>in the Neotropic

A survey for entomopathogenic fungi of Musca domestica adults was conducted in poultry houses in La Plata, Buenos Aires province, Argentina, during the years 2002 and 2003. Adult house flies were found infected with the fungus Beauveria bassiana (Bals.) Vuill. (Deuteromycotina: Hyphomycetes) from field collections, with a natural infected prevalence between 0.4–1.45%. This is the first record of natural infections of house flies caused by B. bassiana for the neotropics. Pathogenicity assays under laboratory conditions showed 94% adult mortality at 14 days post challenge. CIC fellow     

Effects of chickens on the prevalence of infestation and population density of Triatoma infestans in rural houses of north-west Argentina

Abstract Effects of the presence of chickens on population density of the bug Triatoma infestans , principal vector of Chagas disease, were investigated by standardized sampling (indoors and peridomestically) from sixty-eight houses of three rural communities in north-west Argentina, during March 1992.
The domiciliary density of T. infestans increased linearly with the percentage of bugs that fed on chickens, as identified by agar double-diffusion tests. Bug density was significantly higher in houses where hens usually nested indoors than in those where they did not, as determined by concurrent direct observations and interviews of householders. Multiple linear regression analysis of domiciliary bug density on (a) the total number of people, dogs and cats per house; (b) the percentage of domiciliary bugs that fed on chickens, or (c) the indoor-brooding habit of hens, showed the two variables (b, c) related to chickens as significant predictors in each regression model. Inclusion both variables representing chickens increased the fit significantly. Addition of other potentially confounding factors (domestic insecticide use, type of roof and walls of house) did not affect the significant variables retained in the best-fitting regression model.
Peridomestic infestation was positively associated with the household number of fowls. Chickens were the main bloodmeal source of peridomestic T.infestans populations. Human-fed bugs were detected in peridomestic sites of sixteen houses, indicating active dispersal of adults and large nymphal instars from bedroom areas.
Exclusion of hens from domiciliary areas and promotion of chicken sheds, of an appropriate design that would not harbour bug populations, should limit the triatomine population growth rate and reduce the risk of infestation.     

Epidemiology of dust-mite-related disease

For many years it has been suggested that allergens derived from the house dust mite played a major role in the pathogenesis of asthma, eczema and some cases of allergic rhinitis. Recently, house dust mite allergens have been purified and specific immunoassays developed with which exposure to house dust mites and their allergens can be more easily determined. Using these tools, epidemiological studies have provided confirmatory evidence that not only is house dust mite exposure associated with the majority of cases of asthma in children and young adults, but that it is causally related to the development of asthma.     

Susceptibility of black soldier fly (Diptera: Stratiomyidae) larvae and adults to four insecticides

Dosage-mortality regressions were determined for black soldier fly, Hermetia illucens (L.), larvae fed cyromazine or pyriproxifen treated media. Cyromazine LC50 for larvae dying before becoming prepupae ranged from 0.25 to 0.28 ppm with dosage-mortality regression slopes between 5.79 and 12.04. Cyromazine LC50s for larvae dying before emergence ranged from 0.13 to 0.19 ppm with dosage-mortality regression slopes between 3.94 and 7.69. Pyriproxifen dosage-mortality regressions were not generated for larvae failing to become prepupae since <32% mortality was recorded at the highest concentration of 1,857 ppm. LC50s for larvae failing to become adults ranged from 0.10 to 0.12 ppm with dosage mortality-regression slopes between 1.67 and 2.32. Lambda-cyhalothrin and permethrin dosage-mortality regressions were determined for wild adult black soldier flies and house flies, Musca domestica L., and for susceptible house flies. Our results indicate that the wild house fly, unlike the black soldier fly, population was highly resistant to each of these pyrethroids. Regression slopes for black soldier flies exposed to lambda-cyhalothrin were twice as steep as those determined for the wild house fly strain. Accordingly, LC50s for the black soldier fly and susceptible house fly were 10- to 30-fold lower than those determined for wild house flies. The differential sensitivity between wild black soldier flies and house flies might be due to behavioral differences. Adult house flies usually remain in animal facilities with the possibility of every adult receiving pesticide exposure, while black soldier fly adults are typically present only during emergence and oviposition thereby limiting their exposure.