Biological Control of Pest Non-Marine Molluscs: A Pacific Perspective on Risks to Non-Target Organisms.

Classic biological control of pest non-marine molluscs has a long history of disastrous outcomes, and despite claims to the contrary, few advances have been made to ensure that contemporary biocontrol efforts targeting molluscs are safe and effective. For more than half a century, malacologists have warned of the dangers in applying practices developed in the field of insect biological control, where biocontrol agents are often highly host-specific, to the use of generalist predators and parasites against non-marine mollusc pests. Unfortunately, many of the lessons that should have been learned from these failed biocontrol programs have not been rigorously applied to contemporary efforts. Here, we briefly review the failures of past non-marine mollusc biocontrol efforts in the Pacific islands and their adverse environmental impacts that continue to reverberate across ecosystems. We highlight the fact that none of these past programs has ever been demonstrated to be effective against targeted species, and at least two (the snails Euglandina spp. and the flatworm Platydemus manokwari) are implicated in the extinction of hundreds of snail species endemic to Pacific islands. We also highlight other recent efforts, including the proposed use of sarcophagid flies and nematodes in the genus Phasmarhabditis, that clearly illustrate the false claims that past bad practices are not being repeated. We are not making the claim that biocontrol programs can never be safe and effective. Instead, we hope that in highlighting the need for robust controls, clear and measurable definitions of success, and a broader understanding of ecosystem level interactions within a rigorous scientific framework are all necessary before claims of success can be made by biocontrol advocates. Without such amendments to contemporary biocontrol programs, it will be impossible to avoid repeating the failures of non-marine mollusc biocontrol programs to date.

Extinction in a hyperdiverse endemic Hawaiian land snail family and implications for the underestimation of invertebrate extinction.

The International Union for Conservation of Nature (IUCN) Red List includes 832 species listed as extinct since 1600, a minuscule fraction of total biodiversity. This extinction rate is of the same order of magnitude as the background rate and has been used to downplay the biodiversity crisis. Invertebrates comprise 99% of biodiversity, yet the status of a negligible number has been assessed. We assessed extinction in the Hawaiian land snail family Amastridae (325 species, IUCN lists 33 as extinct). We did not use the stringent IUCN criteria, by which most invertebrates would be considered data deficient, but a more realistic approach comparing historical collections with modern surveys and expert knowledge. Of the 325 Amastridae species, 43 were originally described as fossil or subfossil and were assumed to be extinct. Of the remaining 282, we evaluated 88 as extinct and 15 as extant and determined that 179 species had insufficient evidence of extinction (though most are probably extinct). Results of statistical assessment of extinction probabilities were consistent with our expert evaluations of levels of extinction. Modeling various extinction scenarios yielded extinction rates of 0.4-14.0% of the amastrid fauna per decade. The true rate of amastrid extinction has not been constant; generally, it has increased over time. We estimated a realistic average extinction rate as approximately 5%/decade since the first half of the nineteenth century. In general, oceanic island biotas are especially susceptible to extinction and global rate generalizations do not reflect this. Our approach could be used for other invertebrates, especially those with restricted ranges (e.g., islands), and such an approach may be the only way to evaluate invertebrates rapidly enough to keep up with ongoing extinction.

Air travel and chronic obstructive pulmonary disease: a new algorithm for pre-flight evaluation.

BACKGROUND: The reduced pressure in the aircraft cabin may cause significant hypoxaemia and respiratory distress in patients with chronic obstructive pulmonary disease (COPD). Simple and reliable methods for predicting the need for supplemental oxygen during air travel have been requested. OBJECTIVE: To construct a pre-flight evaluation algorithm for patients with COPD. METHODS: In this prospective, cross-sectional study of 100 patients with COPD referred to hypoxia-altitude simulation test (HAST), sea level pulse oximetry at rest (SpO(2 SL)) and exercise desaturation (SpO(2 6MWT)) were used to evaluate whether the patient is fit to fly without further assessment, needs further evaluation with HAST or should receive in-flight supplemental oxygen without further evaluation. HAST was used as the reference method. RESULTS: An algorithm was constructed using a combination of SpO(2 SL) and SpO(2 6MWT). Categories for SpO(2 SL) were >95%, 92-95% and <92%, the cut-off value for SpO(2 6MWT) was calculated as 84%. Arterial oxygen pressure (PaO(2 HAST)) <6.6 kPa was the criterion for recommending supplemental oxygen. This algorithm had a sensitivity of 100% and a specificity of 80% when tested prospectively on an independent sample of patients with COPD (n=50). Patients with SpO(2 SL) >95% combined with SpO(2 6MWT) ≥84% may travel by air without further assessment. In-flight supplemental oxygen is recommended if SpO(2 SL)=92-95% combined with SpO(2 6MWT) <84% or if SpO(2 SL) <92%. Otherwise, HAST should be performed. CONCLUSIONS: The presented algorithm is simple and appears to be a reliable tool for pre-flight evaluation of patients with COPD.

COPD and air travel: oxygen equipment and preflight titration of supplemental oxygen.

BACKGROUND: Patients with COPD may need supplemental oxygen during air travel to avoid development of severe hypoxemia. The current study evaluated whether the hypoxia-altitude simulation test (HAST), in which patients breathe 15.1% oxygen simulating aircraft conditions, can be used to establish the optimal dose of supplemental oxygen. Also, the various types of oxygen-delivery equipment allowed for air travel were compared. METHODS: In a randomized crossover trial, 16 patients with COPD were exposed to alveolar hypoxia: in a hypobaric chamber (HC) at 2,438 m (8,000 ft) and with a HAST. During both tests, supplemental oxygen was given by nasal cannula (NC) with (1) continuous flow, (2) an oxygen-conserving device, and (3) a portable oxygen concentrator (POC). RESULTS: PaO(2) kPa (mm Hg) while in the HC and during the HAST with supplemental oxygen at 2 L/min (pulse setting 2) on devices 1 to 3 was (1) 8.6 ± 1.0 (65 ± 8) vs 12.5 ± 2.4 (94 ± 18) (P < .001), (2) 8.6 ± 1.6 (64 ± 12) vs 9.7 ± 1.5 (73 ± 11) (P < .001), and (3) 7.7 ± 0.9 (58 ± 7) vs 8.2 ± 1.1 (62 ± 8) (P= .003), respectively. CONCLUSIONS: The HAST may be used to identify patients needing supplemental oxygen during air travel. However, oxygen titration using an NC during a HAST causes accumulation of oxygen within the facemask and underestimates the oxygen dose required. When comparing the various types of oxygen-delivery equipment in an HC at 2,438 m (8,000 ft), compressed gaseous oxygen with continuous flow or with an oxygen-conserving device resulted in the same PaO(2), whereas a POC showed significantly lower PaO(2) values. TRIAL REGISTRY: ClinicalTrials.gov; No.: Identifier: NCT01019538; URL: clinicaltrials.gov.

Pulse oximetry in the preflight evaluation of patients with chronic obstructive pulmonary disease.

INTRODUCTION: In a British Thoracic Society (BTS) statement on preflight evaluation of patients with respiratory disease, sea level pulse oximetry (Spo2sl) is recommended as an initial assessment. The present study aimed to evaluate if the BTS algorithm can be used to identify chronic obstructive pulmonary disease (COPD) patients in need of supplemental oxygen during air travel, i.e. patients with an in-flight PaO2 < 6.6 kPa (50 mmHg). METHODS: There were 100 COPD patients allocated to groups according to the BTS algorithm: Spo2sl > 95%, Spo2sl 92-95% without additional risk factors; Spo2sl 92-95% with additional risk factors; Spo2sl < 92%; and patients using domiciliary oxygen. Pulse oximetry, arterial blood gases, and an hypoxia-altitude simulation test (HAST) to simulate a cabin altitude of 2438 m (8000 ft), were performed. RESULTS: The percentage of patients in the various groups dropping below 6.6 kPa during HAST were: Spo2sl > 95%: 30%; Spo2sl 92-95% without additional risk factors: 67%; Spo2sl 92-95% with additional risk factors: 70%; Spo2sl < 92%: 83%; and patients using domiciliary oxygen: 81%. In patients dropping below P(a)o(2) 6.6 kPa, supplemental oxygen of median 1 L x min(-1) was needed to exceed this limit. DISCUSSION: If in-flight P(a)o(2) > or = 6.6 kPa is regarded as a strict requirement, the use of pulse oximetry as an initial assessment in the preflight evaluation of COPD patients, as suggested by the BTS, might not discriminate adequately between patients who fulfill the indications for supplemental oxygen during air travel, and patients who can travel without such treatment.