Genotype X Environment Response of ‘Matooke’ Hybrids (Naritas) to Pseudocercospora fijiensis, the Cause of Black Sigatoka in Banana

Growing bananas resistant to Pseudocercospora fijiensis, the cause of black Sigatoka, is the preferred disease control strategy for resource-poor farmers. Banana breeding programs in east Africa have developed 27 Matooke hybrids (commonly known as NARITAs) with higher yields than local landraces. To assess the response of NARITA hybrids to P. fijiensis, 22 hybrids were evaluated under natural field conditions in four locations—Kawanda and Mbarara in Uganda, and Maruku, and Mitarula in Tanzania—between 2016 and 2018 for three crop cycles. Black Sigatoka was visually assessed and the area under the disease progress curve calculated for each plant over time. Significant differences (p < 0.001) were observed between genotypes, environments, and their interaction. The highest contributor to black Sigatoka severity (39.1%) was the environment, followed by the genotype (37.5%) and the genotype Χ environment interaction (GEI) (23.4%). NARITA 2, 7, 14, 21 and 23 were resistant and the most stable hybrids across locations. If other attributes such as the yield and taste are acceptable to end-users, these hybrids can be released to farmers in the region to replace highly susceptible landraces. Mitarula was identified as an ideal site for evaluating banana against black Sigatoka and should be used as a representative location to minimize costs of disease evaluations.

Engineered Orange Ectopically Expressing the Arabidopsis β-Caryophyllene Synthase Is Not Attractive to Diaphorina citri, the Vector of the Bacterial Pathogen Associated to Huanglongbing

Huanglongbing (HLB) is a destructive disease, associated with psyllid-transmitted phloem-restricted pathogenic bacteria, which is seriously endangering citriculture worldwide. It affects all citrus species and cultivars regardless of the rootstock used, and despite intensive research in the last decades, there is no effective cure to control either the bacterial species (Candidatus Liberibacter spp.) or their insect vectors (Diaphorina citri and Trioza erytreae). Currently, the best attempts to manage HLB are based on three approaches: (i) reducing the psyllid population by intensive insecticide treatments; (ii) reducing inoculum sources by removing infected trees, and (iii) using nursery-certified healthy plants for replanting. The economic losses caused by HLB (decreased fruit quality, reduced yield, and tree destruction) and the huge environmental costs of disease management seriously threaten the sustainability of the citrus industry in affected regions. Here, we have generated genetically modified sweet orange lines to constitutively emit (E)-β-caryophyllene, a sesquiterpene repellent to D. citri, the main HLB psyllid vector. We demonstrate that this alteration in volatile emission affects behavioral responses of the psyllid in olfactometric and no-choice assays, making them repellent/less attractant to the HLB vector, opening a new alternative for possible HLB control in the field.

Calculating the economic burden of presumed microbial keratitis admissions at a tertiary referral centre in the UK

Purpose Microbial keratitis (MK) is the most common non-surgical ophthalmic emergency admission in the UK. However, few prospective health-economic studies of MK have been performed, and no specific healthcare resources group (HRG) code exists. This study is designed to determine the feasibility of a data collection tool derived from the microbiology ophthalmology group (MOG) clinical record form, to enable quantification of direct costs of inpatient care, as well as prospective capture of epidemiological data relating to outcomes of MK. Methods Clinical, demographic and economic data were collected retrospectively between January and December 2013 for 101 consecutive patients admitted with MK, using an adaption of the MOG toolset. The direct cost of admission (COA) was calculated using national reference costs and compared to actual income to generate profit/deficit profiles for individual patients. Indices of multiple deprivation were used to assess effect of deprivation on the COA. Results The total income generated through discharge coding was £252,116, compared to a COA of £357,075, yielding a deficit of £104,960 (median: £754 per patient). The cost deficit increased significantly with length of stay (LOS, p < 0.001), whilst patients with short LOS were income generators; cost neutrality occurred at 4.8 days. Greater socioeconomic deprivation was also associated with a significantly higher cost deficit. Conclusion LOS is the key driver for COA of care for MK admissions. Protocols should encourage discharge of patients who are able to self-administer treatment after the sterilisation phase. The MOG-derived data collection toolset captures pertinent clinical data for quantification of COA. Further development into a multiuser and multisite platform is required for robust prospective testing, together with expansion to capture indirect costs of disease burden, including impact of treatment, visual morbidity and quality of life.

The social costs of disease

The goal of this work was to observe and analyze health inequalities, taking into consideration the influence that the social background of individuals has in the production and reproduction of inequalities. Taking ISTAT reports as databases, which concern aspects of daily life, the results - also confirmed by the literature and by countless empirical studies on the subject - agree with the thesis according to, in later life, the decline in the state of health appears to be delayed for subjects who occupy a highest social positions and a higher educational qualification, compared to those who are in disadvantaged socio-economic conditions and with a lower educational qualification. Differences that are also recorded in the purchase and consumption of drugs.

Evolution of behavioral resistance in host-pathogen systems

Behavioral resistance to parasites is widespread in animals, yet little is known about the evolutionary dynamics that have shaped these strategies. We show that theory developed for the evolution of physiological parasite resistance can only be applied to behavioral resistance under limited circumstances. We find that accounting explicitly for the behavioral processes, including the detectability of infected individuals, leads to novel dynamics that are strongly dependent on the nature of the costs and benefits of social interactions. As with physiological resistance, the evolutionary dynamics can also lead to mixed strategies that balance the costs of disease risk and the benefits of social interaction, with implications for understanding avoidance strategies in human disease outbreaks.

Breeding for Resistance to Husk Spot Disease in Macadamia

In Australian macadamia orchards, significant decreases in saleable nuts have been reported due to husk spot caused by the fungal pathogen, Pseudocercospora macadamiae. In some cultivars, husk spot induces early fruit abscission. This may result in under developed nuts and consequently, increased proportions of commercial rejects. While fungicides are able to reduce impacts of husk spot, breeding for resistance offers a cost-effective and sustainable control option. Quantification of genetic variation for resistance in Australian macadamia breeding germplasm will assist selection. Previous husk spot studies have utilised different inoculation methods including the insertion of diseased husk into tree canopies and the direct application of P. macadamiae suspensions to fruit. Insertion of diseased husk best reflects natural infection processes; however, it requires rainfall or overhead irrigation to disperse spores and may result in the delivery of unequal quantities of inoculum. Different disease parameters have also been measured to compare susceptibility, including proportions of diseased fruit, mean number of lesions per fruit or mean diameter of chlorosis or necrotic lesions. It is unknown which of these parameters are most valuable to assess when screening for resistance. Determining the proportions of variation in such phenotypic traits that is due to genetic variance could identify which of these will better respond to selection. Finally, the use of marker assisted selection may reduce time and costs of disease screening, but no studies have investigated associations between markers and susceptibility to husk spot. In this study, breeding progeny and parents and wild accessions will be screened for husk spot resistance. Repeatability of different inoculation methods will be compared. The heritability of parameters used to measure husk spot incidence and severity will be estimated. Analysis will be undertaken to identify genetic markers associated with resistance. Screening of a wide genetic base for husk spot resistance will enable selection of parents for current breeding. Optimisation of inoculation and phenotypic screening methods and the identification of markers associated with resistance will increase the efficiency of future trials.

Perception, motivators and obstacles of biosecurity in cattle production

Farm biosecurity includes the prevention of disease transmission within and between farms. Two studies were set up to investigate what motivates and withholds farmers to implement biosecurity measures. The first study aimed to assess the perception of cattle farmers towards biosecurity and to identify possible reasons for its low application. This study consisted of a focus group discussion, of which the trends were used to develop a questionnaire for Flemish cattle farmers. Although the 91 participating farmers were familiar with several measures, they associated them with disease prevention rather than biosecurity. Nearly all farmers (98%) identified their herd veterinarian as their main source of information. Twenty percent and 32% of the respondents were convinced that the implementation of biosecurity would cost them more money and time, respectively. Finally, 80% of the farmers saw room for improvement of their herd, but indicated a need for practical information. The second study aimed to identify the key elements of twenty preselected biosecurity measures, motivators and obstacles for their implementation. They were judged by twenty-two cattle stakeholders, such as farmers, veterinarians and advisors, on feasibility, efficacy and return on investment. A box for parturition, a plan for rodent control and cleaning and disinfection of the stables scored highest overall. The lowest scoring measures were showering before entering the stables and an animal-free period of 24 hours. Their return on investment scored very low, since high investments are required. For a farmer to understand why biosecurity is beneficial, he must understand all risks and costs of disease and how biosecurity may reduce these risks and costs.