Integrated Control Program Research Articles

Modelling Co-Infection with Malaria and Lymphatic Filariasis

Malaria and lymphatic filariasis (LF) continue to cause a considerable public health burden globally and are co-endemic in many regions of sub-Saharan Africa. These infections are transmitted by the same mosquito species which raises important questions about optimal vector control strategies in co-endemic regions, as well as the effect of the presence of each infection on endemicity of the other; there is currently little consensus on the latter. The need for comprehensive modelling studies to address such questions is therefore significant, yet very few have been undertaken to date despite the recognised explanatory power of reliable dynamic mathematical models. Here, we develop a malaria-LF co-infection modelling framework that accounts for two key interactions between these infections, namely the increase in vector mortality as LF mosquito prevalence increases and the antagonistic Th1/Th2 immune response that occurs in co-infected hosts. We consider the crucial interplay between these interactions on the resulting endemic prevalence when introducing each infection in regions where the other is already endemic (e.g. due to regional environmental change), and the associated timescale for such changes, as well as effects on the basic reproduction number R0 of each disease. We also highlight potential perverse effects of vector controls on human infection prevalence in co-endemic regions, noting that understanding such effects is critical in designing optimal integrated control programmes. Hence, as well as highlighting where better data are required to more reliably address such questions, we provide an important framework that will form the basis of future scenario analysis tools used to plan and inform policy decisions on intervention measures in different transmission settings.

Prevalence of Trachoma in the Far North Region of Cameroon: Results of a Survey in 27 Health Districts

BackgroundCameroon is known to be endemic with trachoma. To appreciate the burden of the disease and facilitate the national planning of trachoma control in the integrated control program for the neglected tropical diseases, an epidemiological mapping of trachoma was conducted in the Far North region in 2010–11.MethodologyA cross-sectional, cluster random sampling survey was carried out. The survey focused on two target populations: children aged 1 to 9 years for the prevalence of active trachoma and those aged 15 and over for the prevalence of trichiasis (TT). The sample frame was an exhaustive list of villages and neighborhoods of Health Districts (HDs). The World Health Organization simplified trachoma grading system was used for the recognition and registration of cases of trachoma.Principal Findings48,844 children aged 1 to 9 years and 41,533 people aged 15 and over were examined. In children aged 1–9 years, the overall prevalence of trachomatous inflammation–follicular (TF) was 11.2% (95% confidence intervals (CI): 11.0–11.5%). More girls were affected than boys (p = 0.003). Thirteen (13) of 27 HDs in the region showed TF prevalence of ≥10%. The overall TT prevalence was 1.0% (95% CI: 0.9–1.1%). There were estimated 17193 (95% CI: 12576–25860) TT cases in the region. The prevalence of blindness was 0.04% (95% CI: 0.03–0.07%) and visual impairment was 0.09% (95% CI: 0.07–0.13%).Conclusions/SignificanceThe survey confirmed that trachoma is a public health problem in the Far North region with 13 HDs qualified for district-level mass drug administration with azithromycin. It provided a foundation for the national program to plan and implement the SAFE strategy in the region. Effort must be made to find resources to provide the surgical operations to the 17193 TT cases and prevent them from becoming blind.

Effects of temperature and adult nutrition on the development of Acanthoscelides macrophthalmus, a natural enemy of an invasive tree, Leucaena leucocephala

Leucaena leucocephala (Lam.) de Wit (Fabales: Fabaceae; leucaena) is an exceptionally invasive weed in South-East Asia (due to its long flowering period and excessive seed output) causing considerable economic losses in Taiwan. A seed predator originating from Central America and inadvertently introduced to South-East Asia, Acanthoscelides macrophthalmus (Schaeffer) (Coleoptera: Chrysomelidae: Bruchinae), is considered to be a potential augmentative biocontrol agent to check the spread of leucaena. To evaluate the feasibility of using A. macrophthalmus for biological control we investigated its development under six constant temperatures (15–35°C). The relationship between temperature and developmental rate was evaluated using three developmental models of which the Brière model was the best fit for the empirical data. The lower developmental threshold (T0), estimated by linear regression, was 12.8°C. The thermal constant was 632.8 degree-days (DD) for total development (egg to adult emergence). The proportion of females was highest and lowest at the extreme temperatures, 15°C (100%) and 31°C (36.4%), respectively. Given the compatibility between its bionomic parameters (the optimal temperature for development and highest proportion of females) and the local daily average temperatures in Taiwan, augmentative annual releases of beetles to restrict the spread of L. leucocephala appear to be a promising solution. Given the finding that the adult of A. macrophthalmus can effectively elongate its life span and increase its population densities by feeding on nutrient supplements in the field (e.g., saccharose), we infer that A. macrophthalmus can be used effectively for restricting the expansion of L. leucocephala in an integrated control program.

Recent Insights into Nosocomial Infections : A Neglected Condition

Nosocomial infections (NI), also known as hospital acquired infection (HAI), is infection whose development is favoured by a hospital environment, such as one acquired by a patient during a hospital visit or one developing among hospital staff. Such infections include fungal and bacterial infections and are aggravated by the reduced resistance of individual patients. Nosocomial infections continues to be of major clinical and epidemiologic importance in developing countries as it constitutes a major source of morbidity, mortality and significant incremental health care expense for the hospitalized patient, despite major advances in clinical sciences. As per the Study on the Efficacy of Nosocomial Infection Control (SENIC) routine surveillance of NI has become an integral part of infection control and quality assurance in US hospitals because it's potential of reducing nosocomial infections. Studies performed in the United States have demonstrated that an integrated infection control program that includes targeted device-associated surveillance can reduce the incidence of nosocomial infection by as much as 30% and lead to reduced health care costs.

Continuing the child survival revival

There is much to celebrate in child health. Over the past 20 years, global mortality among children younger than 5 years has decreased by 41%, from 87 deaths per 1000 livebirths in 1990 to 51 in 2011. 1 UNICEFWHOWorld BankUNLevels and trends in child mortality: report 2012. United Nations Children's Fund, New York2012 Google Scholar During the same period, development assistance for maternal, newborn, and child health has increased, and has even done so through the global economic crisis. 2 The Institute for Health Metrics and EvaluationFinancing global health: the end of the golden age? Institute for Health Metrics and Evaluation, Seattle, WA2012 Google Scholar Recent international initiatives, such as Every Woman Every Child, the UN Commission on Life-Saving Commodities for Women and Children, and A Promise Renewed, have also reinvigorated the child survival agenda. But the job is far from finished. Time trends hide the real tragedy: 6·9 million children under the age of 5 years still died in 2011, largely from preventable causes. 1 UNICEFWHOWorld BankUNLevels and trends in child mortality: report 2012. United Nations Children's Fund, New York2012 Google Scholar Furthermore, the world is not on track to meet Millennium Development (MDG) Goal 4, a two-thirds reduction in child deaths between 1990 and 2015. 3 UNMillennium Development Goals. Goal 4: reduce child mortality. http://www.un.org/millenniumgoals/childhealth.shtml Google Scholar Global burden of childhood pneumonia and diarrhoeaDiarrhoea and pneumonia are the leading infectious causes of childhood morbidity and mortality. We comprehensively reviewed the epidemiology of childhood diarrhoea and pneumonia in 2010–11 to inform the planning of integrated control programmes for both illnesses. We estimated that, in 2010, there were 1·731 billion episodes of diarrhoea (36 million of which progressed to severe episodes) and 120 million episodes of pneumonia (14 million of which progressed to severe episodes) in children younger than 5 years. Full-Text PDF Interventions to address deaths from childhood pneumonia and diarrhoea equitably: what works and at what cost?Global mortality in children younger than 5 years has fallen substantially in the past two decades from more than 12 million in 1990, to 6·9 million in 2011, but progress is inconsistent between countries. Pneumonia and diarrhoea are the two leading causes of death in this age group and have overlapping risk factors. Several interventions can effectively address these problems, but are not available to those in need. We systematically reviewed evidence showing the effectiveness of various potential preventive and therapeutic interventions against childhood diarrhoea and pneumonia, and relevant delivery strategies. Full-Text PDF Bottlenecks, barriers, and solutions: results from multicountry consultations focused on reduction of childhood pneumonia and diarrhoea deathsMillions of children still die unnecessarily from pneumonia and diarrhoea, mainly in resource-poor settings. A series of collaborative consultations and workshops involving several hundred academic, public health, governmental and private sector stakeholders were convened to identify the key barriers to progress and to issue recommendations. Bottlenecks impairing access to commodities included antiquated supply management systems, insufficient funding for drugs, inadequate knowledge about interventions by clients and providers, health worker shortages, poor support for training or retention of health workers, and a failure to convert national policies into action plans. Full-Text PDF Ending of preventable deaths from pneumonia and diarrhoea: an achievable goalGlobal under-5 mortality has fallen rapidly from 12 million deaths in 1990, to 6·9 million in 2011; however, this number still falls short of the target of a two-thirds reduction or a maximum of 4 million deaths by 2015. Acceleration of reductions in deaths due to pneumonia and diarrhoea, which together account for about 2 million child deaths every year, is essential if the target is to be met. Scaling up of existing interventions against the two diseases to 80% and immunisation to 90% would eliminate more than two-thirds of deaths from these two diseases at a cost of US$6·715 billion by 2025. Full-Text PDF

Epidemiology of intestinal schistosomiasis and soil transmitted helminthiasis among primary school children in Gorgora, Northwest Ethiopia

ObjectiveTo assess the prevalence and intensity of intestinal schistosomiasis and soil transmitted helminthiasis among primary school children in Gorgora, Northwest Ethiopia. MethodsA cross-sectional epidemiological study was carried out in Gorgora primary school in Northwest Ethiopia from November to December 2010. Stool sample was collected from 326 children (170 male and 156 female) and examined by Kato-Katz technique for intestinal schistosomiasis and soil transmitted helminth infection. ResultsA total of 120 children (56 males and 64 females) were positive for single or multiple parasitic infection. Four helminth parasite species were identified and the most prevalent was Ascaris lumbricoides (A. lumbricoides) (16.60%), followed by Schistosoma mansoni (S. mansoni) (10.10%), hookworm (5.50%) and Trichuris trichiura (T. trichiura) (4.60%). Furthermore, 1.84%, 2.76% and 2.45% of the study participants were co-infected with Hookworm &A. lumbricoides, A. lumbricoides &S. mansoni and A. lumbricoides &T. trichiura, respectively. ConclusionsThe high prevalence of intestinal schistosomiasis and soil-transmitted helminthiasis observed in the study area shows the need of integrated control programme including periodic deworming, improving sanitation and access to clean water, appropriate health education and environmental measures to have a lasting impact on transmission.

Towards an effective control programme of soil-transmitted helminth infections among Orang Asli in rural Malaysia. Part 1: Prevalence and associated key factors

BackgroundDespite the continuous efforts to improve the quality of life of Orang Asli (Aborigines) communities, these communities are still plagued with a wide range of health problems including parasitic infections. The first part of this study aimed at determining the prevalence of soil-transmitted helminth (STH) infections and identifying their associated factors among rural Orang Asli children.MethodsA cross-sectional study was carried out among 484 Orang Asli children aged ≤ 15 years (235 females and 249 males) belonging to 215 households from 13 villages in Lipis district, Pahang, Malaysia. Faecal samples were collected and examined by using formalin-ether sedimentation, Kato Katz and Harada Mori techniques. Demographic, socioeconomic, environmental and behavioural information were collected by using a pre-tested questionnaire.ResultsOverall, 78.1% of the children were found to be infected with one or more STH species. The prevalence of trichuriasis, ascariasis and hookworm infections were 71.7%, 37.4% and 17.6%, respectively. Almost all, three quarters and one fifth of trichuriasis, ascariasis and hookworm infections, respectively, were of moderate-to-heavy intensities. Multiple logistic regression analysis showed that age of ≥ 6 years (school-age), using unsafe water supply as a source for drinking water, absence of a toilet in the house, large family size (≥ 7 members), not washing hands before eating, and not washing hands after defecation were the key factors significantly associated with STH among these children.ConclusionThis study reveals an alarmingly high prevalence of STH among Orang Asli children and clearly brings out an urgent need to implement school-based de-worming programmes and other control measures like providing a proper sanitation, as well as a treated drinking water supply and proper health education regarding good personal hygiene practices. Such an integrated control program will help significantly in reducing the prevalence and intensity of STH in Orang Asli communities.

Genetic polymorphism at the cytochrome oxidase I gene in mediterranean populations of Batrocera Oleae (Diptera: Tephritidae)

AbstractThe tephritid Bactrocera oleae (Gmelin) is a harmful pest of olive crops that cause important agricultural and economic losses in the Mediterranean area where 90% of the world olive trees are cultivated. The knowledge of the genetic diversity in insect pest species populations is critical for decisions concerning appropriate control management strategies. In the present work, the genetic variability within and among 7 populations ‐five from Spain, one from Italy and one from Tunisia‐, was assessed by sequencing 1151 bp of the COI gene. A total of 21 haplotypes were observed. The intraspecific diversity was high, particularly in the Spanish populations (haplotype and nucleotide diversity 0.84 and 0.00137, respectively). However, the genetic differentiation among the populations was low in the case of Spanish ones (Fst between 0 and 0.041), and higher –and statistically significant– when comparing with the Italian and Tunisian samples. The haplotypes distribution and the PCoA analysis show three clear groups of populations: Spanish, Italian and Tunisian. The results might indicate the length of time elapsed since B. oleae became established in the Mediterranean region, the large effective sizes expected of its populations and the high gene flow among Iberian populations. The information could be relevant for integrated control programmes coordination.

Control of Ceratophyllum demersum L. present in Laboratory by using Integrated Control Program

Control of Ceratophyllum demersum L. present in Laboratory by using Integrated Control Program

Vectors and Vector-Borne Diseases in Turkey

In Turkey, arthropod-borne diseases such as human babesiosis, dirofilariasis, leishmaniasis, malaria, lymphatic filariasis, onchocerciasis, anthrax, bartonellosis, louse-borne relapsing fever, lyme disease, plague, trench fever, tularemia, epidemic typhus, tick-borne typhus, Crimean-Congo hemorrhagic fever, phlebovirus infections, tick-borne encephalitis and west nile virus in humans; animal trypanosomiasis, avian haemosporidiasis, babesiosis, canine hepatozoonosis, canine lesihmaniosis, dipetalonemiasis, dirofilariosis, habronemiasis, onchocerciasis, parafilariasis, setariasis, theileriosis, thelaziasis, anaplasmosis, ehrlichiosis, feline infectious anemia, akabane, bluetongue, bovine ephemeral fever, equine infectious anemia, louping ill, west nile virus, colony collapse disorders (CCD) were reported in domestic animals and Wolbachia endobacteria infection was also reported in mosquitos so far. On the other hand, aphids (Aphididae), leafhoppers (Cicadellidae), white flies (Aleyrodidae), beetles (Coleoptera), trips (Thysanoptera), gal mites (Eriophyidae), and nematodes are also very important vectors of plant diseases in Turkey. Some of the most harmful plant viruses in the world such as tristeza, plum pox virus, and tomato ringspot viruses are also transmitted by arthropod vectors. In recent years, in spite of changes in ecological balance caused by abandoning agricultural land, use of natural areas to farm, release of rabbits, preventing water flooding, leaving the fields uncultivated, migration from urban to rural areas, hunting of wild animals, the dramatic drop in the number of farm animals, global warming and the strengthening of wild life was probably responsible for the increase of tick populations. The construction of ponds and dams, changes in riverbeds, drying out of swamps and marshes, dense ad-hoc and haphazard construction, changes in picnicking habits, wild irrigation in agriculture, and the use of unsuitable control measures by local authorities, resulted in an increase of flies. This led to an increase in infected vector populations and vector-borne diseases and a decrease in the potential for economic development. In conclusion, it is very important to initiate and develop integrated control programs targeting arthropod vectors, disease agents of human, animal and plants and natural reservoirs. These diseases have been caused high economic losses in Turkey, and therefore they should be further investigated

The effect of high frequency sound on <i>Culicoides</i> numbers collected with suction light traps

Culicoides midges (Diptera: Ceratopogonidae), are involved in the transmission of various pathogens that cause important diseases of livestock worldwide. The use of insect repellents to reduce the attack rate of these insects on livestock could play an important role as part of an integrated control programme against diseases transmitted by these midges. The objective of this study was to determine whether high frequency sound has any repellent effect on Culicoides midges. The number of midges collected with 220 V Onderstepoort white light traps fitted with electronic mosquito repellents (EMRs), emitting 5-20 KHz multi-frequency sound waves, was compared with that of two untreated traps. Treatments were rotated in two replicates of a 4 x 4 randomised Latin square design. Although fewer midges were collected in the two traps fitted with EMRs, the average number collected over eight consecutive nights was not significantly different. The EMRs also had no influence on any of the physiological groups of Culicoides imicola Kieffer or the species composition of the Culicoides population as determined with light traps. The results indicate that high frequency sound has no repellent effect on Culicoides midges. There is therefore no evidence to support their promotion or use in the protection of animals against pathogens transmitted by Culicoides midges.

Toxic effect of herbicides used for water hyacinth control on two insects released for its biological control in South Africa

The integrated control of water hyacinth, Eichhornia crassipes (Martius) Solms-Laubach (Pontederiaceae) has become necessary in South Africa, as biological control alone is perceived to be too slow in controlling the weed. In total, seven insect biological control agents have been released on water hyacinth in South Africa. At the same time, herbicides are applied by the water authorities in areas where the weed continues to be troublesome. This study investigated the assumption that the two control methods are compatible by testing the direct toxicity of a range of herbicide formulations and surfactants on two of the biological control agents released against water hyacinth, the weevil, Neochetina eichhorniae Warner (Coleoptera: Curculionidae) and the water hyacinth mirid, Eccritotarsus catarinensis (Carvalho) (Hemiptera: Miridae). A number of the formulations used resulted in significant mortality of the mirid and the weevil. Products containing 2,4-D amine and diquat as active ingredients caused higher mortality of both agents (up to 80% for the mirid) than formulations containing glyphosate. Furthermore, when surfactants were added to enhance herbicide efficiency, it resulted in increased toxicity to the insects. We recommend that glyphosate formulations should be used in integrated control programmes, and that surfactants be avoided in order to reduce the toxic nature of spray formulations to the insect biological control agents released against water hyacinth.

Determination of the best timing for control application against cotton leaf worm using remote sensing and geographical information techniques

Knowledge of the larval-age distribution in the field is important for prediction purpose and timing of insecticide applications for insect pest management. This studies acts by calculating the average of thermal units in degree-days (dd’s). The average of thermal units required for completion of generation is 544.98, 640.63 and 599.66 degrees-days (°C) as calculated from air temperatures derived from thermograph and satellite images, and soil temperatures from satellite images, respectively, considering 9.89°C as a developmental threshold. These were higher than the estimated value of dd’s based on laboratory data (524.27 degrees-days (°C)). There was a difference between degree days obtained from air temperatures derived from satellite images and thermograph by 59.2 dd’s, this value represented only about 2.85days. In order to improve the predictability, a factor was estimated between them which is 0.81, 0.96 and 0.87 in case of thermograph, soil and air temperature that derived from satellite images so the predicted stages was highly improved. Egg hatching was estimated to be 80% complete by ≈80.45 dd’s. At 174.85 DD, mostly all larvae in the field experiment were from the first to third instars. The presence of more mature larvae (fourth to sixth instars) was not noticed until 197.59 dd’s. These data indicate that, the best timing for control application against Spodoptera littoralis would be at 174.85–197.59 dd’s.The results are important for quick prediction purposes, control timing and also as valuable tools used in an integrated control program for managing S. littoralis in Egypt.

Bovine immunoprotection against Rhipicephalus (Boophilus) microplus with recombinant Bm86-Campo Grande antigen

The southern cattle fever tick, Rhipicephalus (Boophilus) microplus, is no doubt the most economically important ectoparasite of cattle globally. The inappropriate use of chemical acaricides has driven the evolution of resistance in populations of R. (B.) microplus. Anti-tick vaccines represent a technology that can be combined with acaricides in integrated control programs to mitigate the impact of R. (B.) microplus. The recombinant form of Bm86 antigen from the Campo Grande (rBm86-CG) strain of R. (B.) microplus was produced using the Pichiapastoris expression system to test its ability to immunoprotect cattle against tick infestation. Secretion of rBm86-CG by P. pastoris through the bioprocess reported here simplified purification of the antigen. A specific humoral immune response was detected by ELISA in vaccinated cattle. Immunoblot results revealed that polyclonal antibodies from vaccinated cattle recognized a protein in larval extracts with a molecular weight corresponding to Bm86. The rBm86-CG antigen showed 31% efficacy against the Campo Grande strain of R. (B.) microplus infesting vaccinated cattle. The rBm86-CG is an antigen that could be used in a polyvalent vaccine as part of an integrated program for the control of R. (B.) microplus in the region that includes Mato Grosso do Sul.

Laboratory evaluation of the effects of Manilkara subsericea (Mart.) Dubard extracts and triterpenes on the development of Dysdercus peruvianus and Oncopeltus fasciatus

Studies were carried out to evaluate the effects of Manilkara subsericea extracts and triterpenes on the development of two species of agricultural pest insects, Oncopelus fasciatus and Dysdercus peruvianus. All treatments of insects with M. subsericea extracts induced mortality, delayed development and inhibited moulting. Some extracts assayed (FH, FB and FD in D. peruvianus, and FH, FB and FEA in O. fasciatus) also produced body deformities in the few adults that emerged. Other extracts (FH, FEA, FB, FD and LET in both insects), however, induced either permanent (overaged) or extranumerary nymphs, both of which were unable to achieve the adult stage and reproductive status. The insects were also treated with triterpenes (α- and β-amyrin acetates) which showed high lethality at 30 days after treatment and delayed the intermoult period so that overaged nymphs were detected. The results indicate that extracts and triterpenes from Manilkara subsericea act as potent growth inhibitors of phytophagous hemipteran nymphs. It is also concluded that the mixture of several different molecules in the extracts used produces synergic effects that do not occur after using the triterpenes (PFT) alone. These secondary metabolites in the M. subsericea extracts can potentially be used in integrated control programmes against crop pests.

Impact of Salivary Gland Hypertrophy Virus Infection on the Mating Success of Male Glossina pallidipes: Consequences for the Sterile Insect Technique

Many species of tsetse flies are infected by a virus (GpSGHV) that causes salivary gland hypertrophy (SGH). Female Glossina pallidipes (Austen) with SGH symptoms (SGH+) have reduced fecundity and SGH+ male G. pallidipes are unable to inseminate female flies. Consequently, G. pallidipes laboratory colonies with a high prevalence of SGH have been difficult to maintain and have collapsed on several occasions. To assess the potential impact of the release of SGH+ sterile male G. pallidipes on the efficacy of an integrated control programme with a sterile insect technique (SIT) component, we examined the mating efficiency and behaviour of male G. pallidipes in field cages in relation to SGH prevalence. The results showed in a field cage setting a significantly reduced mating frequency of 19% for a male G. pallidipes population with a high prevalence of SGH (83%) compared to 38% for a male population with a low prevalence of SGH (7%). Premating period and mating duration did not vary significantly with SGH status. A high percentage (>80%) of females that had mated with SGH+ males had empty spermathecae. The remating frequency of female G. pallidipes was very low irrespective of the SGH status of the males in the first mating. These results indicate that a high prevalence of SGH+ in G. pallidipes not only affects colony stability and performance but, in view of their reduced mating propensity and competitiveness, releasing SGH+ sterile male G. pallidipes will reduce the efficiency of a sterile male release programme.

Pseudomonas savastanoi pv. savastanoi: some like it knot

Pseudomonas savastanoi pv. savastanoi is the causal agent of olive (Olea europaea) knot disease and an unorthodox member of the P. syringae complex, causing aerial tumours instead of the foliar necroses and cankers characteristic of most members of this complex. Olive knot is present wherever olive is grown; although losses are difficult to assess, it is assumed that olive knot is one of the most important diseases of the olive crop. The last century witnessed a large number of scientific articles describing the biology, epidemiology and control of this pathogen. However, most P. savastanoi pv. savastanoi strains are highly recalcitrant to genetic manipulation, which has effectively prevented the pathogen from benefitting from the scientific progress in molecular biology that has elevated the foliar pathogens of the P. syringae complex to supermodels. A number of studies in recent years have made significant advances in the biology, ecology and genetics of P. savastanoi pv. savastanoi, paving the way for the molecular dissection of its interaction with other nonpathogenic bacteria and their woody hosts. The selection of a genetically pliable model strain was soon followed by the development of rapid methods for virulence assessment with micropropagated olive plants and the analysis of cellular interactions with the plant host. The generation of a draft genome of strain NCPPB 3335 and the closed sequence of its three native plasmids has allowed for functional and comparative genomic analyses for the identification of its pathogenicity gene complement. This includes 34 putative type III effector genes and genomic regions, shared with other pathogens of woody hosts, which encode metabolic pathways associated with the degradation of lignin-derived compounds. Now, the time is right to explore the molecular basis of the P. savastanoi pv. savastanoi-olive interaction and to obtain insights into why some pathovars like it necrotic and why some like it knot. Pseudomonas syringae pv. savastanoi. Kingdom Bacteria; Phylum Proteobacteria; Class Gammaproteobacteria; Family Pseudomonadaceae; Genus Pseudomonas; included in genomospecies 2 together with at least P. amygdali, P. ficuserectae, P. meliae and 16 other pathovars from the P. syringae complex (aesculi, ciccaronei, dendropanacis, eriobotryae, glycinea, hibisci, mellea, mori, myricae, phaseolicola, photiniae, sesami, tabaci, ulmi and certain strains of lachrymans and morsprunorum); when a formal proposal is made for the unification of these bacteria, the species name P. amygdali would take priority over P. savastanoi. Gram-negative rods, 0.4-0.8 × 1.0-3.0 μm, aerobic. Motile by one to four polar flagella, rather slow growing, optimal temperatures for growth of 25-30 °C; oxidase negative, arginine dihydrolase negative; elicits the hypersensitive response on tobacco; most isolates are fluorescent and levan negative, although some isolates are nonfluorescent and levan positive. P. savastanoi pv. savastanoi causes tumours in cultivated and wild olive and ash (Fraxinus excelsior). Although strains from olive have been reported to infect oleander (Nerium oleander), this is generally not the case; however, strains of P. savastanoi pv. nerii can infect olive. Pathovars fraxini and nerii are differentiated from pathovar savastanoi mostly in their host range, and were not formally recognized until 1996. Literature before about 1996 generally names strains of the three pathovars as P. syringae ssp. savastanoi or P. savastanoi ssp. savastanoi, contributing to confusion on the host range and biological properties. Symptoms of infected trees include hyperplastic growths (tumorous galls or knots) on the stems and branches of the host plant and, occasionally, on leaves and fruits. The pathogen can survive and multiply on aerial plant surfaces, as well as in knots, from where it can be dispersed by rain, wind, insects and human activities, entering the plant through wounds. Populations are very unevenly distributed in the plant, and suffer drastic fluctuations throughout the year, with maximum numbers of bacteria occurring during rainy and warm months. Populations of P. savastanoi pv. savastanoi are normally associated with nonpathogenic bacteria, both epiphytically and endophytically, and have been demonstrated to form mutualistic consortia with Erwinia toletana and Pantoea agglomerans, which could result in increased bacterial populations and disease symptoms. Based on preventive measures, mostly sanitary and cultural practices. Integrated control programmes benefit from regular applications of copper formulations, which should be maintained for at least a few years for maximum benefit. Olive cultivars vary in their susceptibility to olive knot, but there are no known cultivars with full resistance to the pathogen. http://www.pseudomonas-syringae.org/; http://genome.ppws.vt.edu/cgi-bin/MLST/home.pl; ASAP access to the P. savastanoi pv. savastanoi NCPPB 3335 genome sequence https://asap.ahabs.wisc.edu/asap/logon.php.

Influence of nitrogen and plant density on the growth and seed production of common ragweed (Ambrosia artemisiifolia L.)

Common ragweed is an important annual weed in crop production, and is also considered to be a serious public health problem. Determination of common ragweed growth under various nitrogen (N) rate and plant density could aid the development of an integrated control program. Greenhouse and field experiments were conducted to determine the effects of N fertilizer and density on common ragweed growth and seed production. In the greenhouse study, the greatest shoot dry matter (SDM) plant−1 was obtained with the 50 and 100 kg N ha−1. In the field experiment, SDM plant−1 in the low density plots responded favorably to the addition of medium and high levels of N compared to the field level of N. With increasing density, ragweed in higher density plots responded only with the highest N rate. The intensity of intraspecific competition increased with increasing density, thus total SDM plant−1 was significantly reduced, regardless of N rate. Intraspecific competition also reduced the reproductive production of common ragweed where seed production decreased as plant density increased. Plants grown at higher density produced less seeds per plant basis; however, they produced a considerable number of seed on a per area land basis, which is important for the survival of the species and further expansion in agricultural land and non-crop areas. Common ragweed is a fast-growing species, capable of producing considerable biomass and seed at various pure stand densities and N rates. It also justifies the need for early season control to prevent seed production.

A Research Agenda for Helminth Diseases of Humans: Modelling for Control and Elimination

Mathematical modelling of helminth infections has the potential to inform policy and guide research for the control and elimination of human helminthiases. However, this potential, unlike in other parasitic and infectious diseases, has yet to be realised. To place contemporary efforts in a historical context, a summary of the development of mathematical models for helminthiases is presented. These efforts are discussed according to the role that models can play in furthering our understanding of parasite population biology and transmission dynamics, and the effect on such dynamics of control interventions, as well as in enabling estimation of directly unobservable parameters, exploration of transmission breakpoints, and investigation of evolutionary outcomes of control. The Disease Reference Group on Helminth Infections (DRG4), established in 2009 by the Special Programme for Research and Training in Tropical Diseases (TDR), was given the mandate to review helminthiases research and identify research priorities and gaps. A research and development agenda for helminthiasis modelling is proposed based on identified gaps that need to be addressed for models to become useful decision tools that can support research and control operations effectively. This agenda includes the use of models to estimate the impact of large-scale interventions on infection incidence; the design of sampling protocols for the monitoring and evaluation of integrated control programmes; the modelling of co-infections; the investigation of the dynamical relationship between infection and morbidity indicators; the improvement of analytical methods for the quantification of anthelmintic efficacy and resistance; the determination of programme endpoints; the linking of dynamical helminth models with helminth geostatistical mapping; and the investigation of the impact of climate change on human helminthiases. It is concluded that modelling should be embedded in helminth research, and in the planning, evaluation, and surveillance of interventions from the outset. Modellers should be essential members of interdisciplinary teams, propitiating a continuous dialogue with end users and stakeholders to reflect public health needs in the terrain, discuss the scope and limitations of models, and update biological assumptions and model outputs regularly. It is highlighted that to reach these goals, a collaborative framework must be developed for the collation, annotation, and sharing of databases from large-scale anthelmintic control programmes, and that helminth modellers should join efforts to tackle key questions in helminth epidemiology and control through the sharing of such databases, and by using diverse, yet complementary, modelling approaches.

Risk Assessment of Selected Insecticides on Tamarixia triozae (Hymenoptera: Eulophidae), a Parasitoid of Bactericera cockerelli (Hemiptera: Trizoidae)

Tamarixia triozae (Burks) (Hymenoptera: Eulophidae) is an important parasitoid of the potato or tomato psyllid, Bactericera cockerelli (Sulc) (Hemiptera: Trizoidae), a serious pest of potato (Solanum tuberosum L.), tomato (Solanum lycopersicum L.), and other solanaceous vegetables in many countries. To produce a marketable crop, insecticides are required when B. cockerelli populations reach economically damaging levels. We evaluated 11 commonly used insecticides for their effects on T. triozae. Glass-surface residues of spinetoram, imidacloprid-cyfluthrin, abamectin, and tolfenpyrad caused 100% mortality of T. triozae in 72 h, and the leaf residue of spinetoram was extremely toxic to T. triozae adults; even 15-d-old residues caused 100% mortality. Cyantraniliprole, fenpyroximate, pymetrozine, spirotetramat, spiromesifen, and chenopodium oil did not cause significant mortality in either glass surface or leaf-residue bioassays. Ingestion of spinetoram, abamectin, and imidacloprid+cyfluthrin (Leverage) by the adults resulted in 100% mortality in 12 h, and tolfenpyrad, 75.0% mortality in 12 h; whereas chenopodium oil and pymetrozine showed moderate effects on adult survival. Ingestion of abamectin, imidacloprid-cyfluthrin, and spinetoram killed all adults in the first day of treatment, whereas female adults in the treatment of pymetrozine lived 80.8 d, which was similar to those in the control. Ingestion of abamectin, imidacloprid-cyfluthrin, chenopodium oil, and spinetoram killed all male adults in the first day, whereas ingestion of other insecticides did not cause significant mortality, but reduced percent parasitism. Abamectin, imidacloprid-cyfluthrin, and spinetoram had the most deleterious effects on T. triozae, and have the least potential for use in integrated control programs using this parasitoid.