Eradication of Norway Rats for Recovery of Seabird Habitat on Langara Island, British Columbia

Introduced Rattus norvegicus (Norway rats) caused the decline of Synthliboramphus antiquus (ancient murrelets) and other seabirds breeding on Langara Island (approximately 3,100 ha), British Columbia. Using funds from the litigation settlement following the Nestucca oil spill, Environment Canada eradicated Norway rats using a technique developed in New Zealand which involved dispensing wax baits containing the anticoagulant brodifacoum at 50 ppm from fixed bait stations. Bait stations were placed every 75 to 100 m on a grid over the entire island (1 station/ha). Rats removed bait for 26 days, after which crews placed baits in protective plastic bags in each bait station. Stations loaded with baits were left on the island and rechecked four times over 2 years, after which bait stations and remaining bait were removed. The eradication succeeded. No signs of rats have been detected on Langara Island and its associated islands since January 1996. No rats were trapped during 1,700 trap‐nights following the poison campaign. Incisor marks of rats were not found on apples or oil‐dipped chew‐sticks. Corvus corax (common ravens) likely suffered greater than 50% mortality from the eradication after apparently gaining access to the poison directly from bait stations and from scavenging rat carcasses. A monitoring and response system is being developed in conjunction with current users of the islands. The success on Langara Island demonstrates how the technique proven on small New Zealand islands of less than 300 ha can be effectively extrapolated to much larger islands.     

Dracunculiasis (guinea worm disease): eradication without a drug or a vaccine

Dracunculiasis, commonly known as guinea worm disease, is a nematode infection transmitted to humans exclusively via contaminated drinking water. The disease prevails in the most deprived areas of the world. No vaccine or medicine is available against the disease: eradication is being achieved by implementing preventive measures. These include behavioural change in patients and communities—such as self-reporting suspected cases to health workers or volunteers, filtering drinking water and accessing water from improved sources and preventing infected individuals from wading or swimming in drinking-water sources—supplemented by active surveillance and case containment, vector control and provision of improved water sources. Efforts to eradicate dracunculiasis began in the early 1980s. By the end of 2012, the disease had reached its lowest levels ever. This paper reviews the progress made in eradicating dracunculiasis since the eradication campaign began, the factors influencing progress and the difficulties in controlling the pathogen that requires behavioural change, especially when the threat becomes rare. The challenges of intensifying surveillance are discussed, particularly in insecure areas containing the last foci of the disease. It also summarizes the broader benefits uniquely linked to interventions against dracunculiasis.     

Spawning and Brood Defense of Smallmouth Bass Under the Process of Invasion into a Novel Habitat

Smallmouth bass, Micropterus dolomieu, known as one of the world's most disastrous invasive species, was introduced into Lake Aoki, central Japan in the last 10 years and is of concern for the conservation of the native biodiversity. We investigated spawning and brood defense under novel conditions to devise measures to eradicate a local population of this species. Compared to their native habitat, the size distribution of nesting males was less skewed to the right in this invasive population but rather a skewed normal distribution probably due to prevention of younger cohorts entering the nesting stock. The number of offspring deposited in nests was not positively related to the size of the nesting male. These observations imply that a shortage of suitable nest sites leads to an escalation in male–male competition, followed by a relaxation of female mate choice based on male size. Further, when presented with a model of a potential predator of the offspring, nesting males reacted individually and the intensity of site tenacity was independent of the male size. We propose that the removal of cover accompanied by the use of native predators of young bass can effectively decelerate the expansion of invasive smallmouth bass.     

Early detection of gastric cancer after Helicobacter pylori eradication due to endoscopic surveillance

Background

Helicobacter pylori eradication therapy is commonly performed to reduce the incidence of gastric cancer. However, gastric cancer is occasionally discovered even after successful eradication therapy. Therefore, we examined the prognosis of gastric cancer patients, diagnosed after successful H. pylori eradication therapy.

Materials and Methods

All‐cause death rates and gastric cancer‐specific death rates in gastric cancer patients who received successful H. pylori eradication treatment was tracked and compared to rates in patients who did not receive successful eradication therapy.

Results

In total, 160 gastric cancer patients were followed‐up for up to 11.7 years (mean 3.5 years). Among them, 53 gastric cancer patients received successful H. pylori eradication therapy prior to gastric cancer diagnosis. During the follow‐up period, 11 all‐cause deaths occurred. In the successful eradication group, the proportion of patients with cancer stage I was higher. The proportions of patients who received curative endoscopic therapy and endoscopic examination in the 2 years prior to gastric cancer diagnosis were also higher in the successful eradication group. Kaplan–Meier analysis of all‐cause death and gastric cancer‐specific death revealed a lower death rate in patients in the successful eradication group (P = .0139, and P = .0396, respectively, log‐rank test). The multivariate analysis showed that endoscopy within 2 years before cancer diagnosis is associated with stage I cancer.

Conclusions

Possible early discovery of gastric cancer after H. pylori eradication due to regular endoscopic surveillance may contribute to better prognosis of patients with gastric cancer.     

A local risk map using field observations of the Asian longhorned beetle to optimize monitoring activities

The Asian longhorned beetle Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae) is one of the most dangerous xylophagous pests affecting broadleaf trees in the world. Eradication programmes are undertaken in non‐native regions, requiring extensive resources and involving high costs. An adapted strategy must be set up to optimize the ratio cost/probability of success. We developed a method to generate a risk index of A. glabripennis presence at a local scale, in the surrounding area of an infestation, using field observations (counts of adult insects, exit holes and infested trees). The method, mathematically based on the bivariate symmetric Laplace distribution, has thus reasonable input requirements. The output risk map is easy to interpret and can be directly used by decision‐makers. We used our approach in three infestations in Switzerland. The risk map represented well the insect pressure (beetle population density). We highlighted the fact that survey boundaries, commonly chosen using constant distances from the infestation, should be selected regarding the spatial distribution of the insect pressure, to prioritize monitoring activities. The risk map provides a helpful instrument for advanced survey planning after a first overview, for example to decide which area and which host trees should be inspected for infestations.     

Effects of adult chill treatments on mate attracting potential for irradiated Mexican fruit fly males

Mexican fruit flies, Anastrepha ludens (Loew), that are reared, sterilized and released for maintenance of a fly free zone in south Texas and for population eradication in California are routinely chilled for 1 to 2 h to facilitate handling and dispersal. While a number of behavioral, physical and physiological characteristics are routinely monitored as part of a quality control program, the effect of the chilling process on the ability of these males to attract wild females has not been evaluated. Tests were performed to compare the mate attracting effectiveness of mass reared, sterilized, chilled males with sterile males that had not been chilled and with recently colonized males. Tests were performed with two recently colonized strains of females in a large cage and males of the three types in plastic cups set on top of the cage. Controls consisted of empty cups. Results showed no significant differences among the three types of males. In tests with the most recently collected (least laboratory adapted) wild strain of females, the chilled males attracted the most females. Fly age and time of day were both significantly related to total attractiveness of males. Number of females responding to males per day increased over the five-day test period. The time period when female response was greatest was variable among the tests.     

Hosts of Mediterranean fruit fly Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) from Broome and the Broome Peninsula, Western Australia

Abstract  In the Kimberley region of Western Australia, Mediterranean fruit fly (medfly) Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) is only established at Broome. From 1998 to 2001 extensive fruit sampling was carried out at Broome during a trial investigating the eradication of medfly from the Kimberley using the sterile insect technique. Fruit was collected from 82 native and introduced plants growing in and surrounding the town of Broome and held for emergence of medfly. Eighteen plants, including the native tree Terminalia petiolaris , were found to be medfly hosts . On the basis of abundance, fruiting phenology and host suitability, eight species (kumquat Fortunella japonica , mango Magnifera indica , Barbados cherry Malpighia glabra , orange jessamine Murraya paniculata , guava Psidium guajava , Pacific almond Terminalia catapa , blackberry tree Terminalia petiolaris and yellow oleander Thevetia peruviana ) were the most important hosts ensuring medfly survival and population growth. Despite medfly being reared from T. petiolaris , it is likely that medfly can only maintain populations in areas close to human habitation, and eradication from these areas would lead to eradication from the whole Kimberley region.