Bartonella Seroreactivity among Persons Experiencing Homelessness During an Outbreak of Bartonella quintana in Denver, Colorado, 2020

During a recent outbreak of Bartonella quintana disease in Denver, 15% of 241 persons experiencing homelessness who presented for SARS-CoV-2 testing were seroreactive for Bartonella. Improved recognition of B. quintana disease and prevention of louse infestation are critical for this vulnerable population.

Salmon louse infestation in wild brown trout populations generates multi-modal mixture distributions

For successful evaluation of the overall effects of salmon louse infestation on brown trout population dynamics, it is crucial to have a realistic understanding of how lice infestation distributions are generated and how they should be interpreted. Here, we simulated the potential effects of spatio-temporal variance in lice larvae densities, temporal variance in sea trout marine migration timing and spatial variance in marine habitat use on lice infestation distributions. We show that, when sampling populations with individual variation in marine behaviour, e.g. from post-smolts to veteran migrants, we must expect multi-modal mixture lice infestation distributions. Applying standard statistical distributions, such as the Poisson, negative binomial or zero-inflated distributions, can be too simplistic and give biased results. Temporary increases in salmon lice load in a given area may have inconsistent effects among individuals of a population and may be critical for vulnerable groups such as post-smolts, dependent on timing. For many analyses, it will be necessary to resolve the contributions from groups of fish with different lice infestation expectations due to spatio-temporal differences in habitat use within the overall mixture distribution. Another consequence is that different data sources, obtained by different methods or sampled at different locations and periods, must be expected to give different lice infestation distributions, even when sampling the same population. We also discuss additional factors that may complicate the interpretation of salmon lice infestation distributions on sea trout, such as lice-induced mortality, and behavioural changes, such as premature return to less saline water for delousing.

Economic Burden Associated with Head Louse (Pediculus humanus capitis) Infestation in Iran

Background: The head louse infestation is a public health issue in the world especially, affecting most people who live in camps, school-aged children and their families. Head lice treatment has economic ramifications that often under calculated. The aim of this study was evaluation of economic burden associated with head louse infestation in Iran. Methods: In a cross-sectional study, 500,002 infestations were diagnosed among suspected head lice infested people who referred to health care system in all provinces of Iran during 2017. Direct and indirect costs related to paid by patients and government systems were extracted by referring to accounting documents and interviews with patients and experts and were recorded in researcher-made forms. Microsoft Excel 2010 software was used for economic burden calculation. Results: The incidence rate of head lice infestation in Iran was 500,002/79,926,270 (625.5 per 100,000 populations). Economic burden of head lice in the country was calculated at 5,790,143$. Direct and indirect costs, governmental cost, out of pocket and total costs of head lice were included 3.14$, 2.84$, 5.98$, 5.60$ and 11.58$ per case respectively. Conclusion: The direct and indirect costs associated with treatment of infestations were relatively high. Therefore, the creation of medical facilities such as availability of diagnostic and treatment strategies can be effective in the control of infestation. The adoption of infestation prevention methods, such as health education to people at risk of infestation, reduces the incidence of head lice and imposition of related treatment costs on governmental health care system and head lice cases.

Treatment of Head Louse Infestation with a Novel Mixture Made of Semi-Crystalline Polymers and Plant Extracts: Blind, Randomized, Controlled, Superiority Trial

The rate of head louse infestations is increasing. Most of the neurotoxic treatments are not reliably ovicidal and are faced with genetic resistance. The treatments based on a mechanical mode of action show no sufficient efficacy, transferring the chances of a cure on a tedious combing or leaving the hair fatty. This double-blinded, randomized, controlled, superiority trial evaluates the efficacy and safety of a novel mixture made of semi-crystalline polymers and plant extracts. Forty-five participants received a single application of either 1% Permethrin lotion or the novel lotion, applied for 15 minutes. Untreated and treated nits were collected and placed in an incubator during 10 days. The worst case intent-to-treat analysis found the novel lotion significantly more effective than 1% Permethrin, with 21/22 (95.5%) participants cured and 9/23 (39.1%), respectively (p < 0.0001). Rate of viable nymphs was 0.5 (2.1) for the new lotion and 40.8 (20.4) for the 1% Permethrin. The new lotion cures head louse infestations, offering an effective alternative treatment, with a high efficacy for inhibiting the hatching of eggs. Its physical actions on lice and their eggs should not be affected by resistance to neurotoxic insecticides.

Phenotypic and genetic variation in lumpfish (Cyclopterus lumpus): applications towards sustainable aquaculture of cleaner fish

Ectoparasitic lice threaten sustainable Atlantic salmon (Salmo salar) aquaculture, as high farm stocking densities facilitate louse infestation thereby increasing mortality rates. Lumpfish (Cyclopterus lumpus) have recently been demonstrated to remove lice and are increasingly deployed onto farms as cleaner fish. Commercial stocks of lumpfish are now produced in hatcheries to meet growing demand from farms across the Atlantic, however, concern grows regarding the long-term viability of this practise due to insufficient knowledge on lumpfish biology. Challenges include understanding how patterns of genetic and phenotypic variation influence performance, whether desirable traits can inform captive breeding, potential impacts on wild populations and whether intraspecific variation in cleaning behaviour can be optimized. Therefore, this thesis examined genetic and phenotypic variation in lumpfish across multiple biological scales, ranging from populations down to family stocks and individuals, investigating factors influencing aquaculture performance. Chapter 1 found genetic structure in populations across the Atlantic, with limited gene flow separating regions of lumpfish aquaculture. Chapter 2 identified phenotypic differences in the body morphology of stocks, including variation in scutes and body depth of northern and southern phenotypes. Sexual dimorphism was identified in the mouth, flag, hump and caudal peduncle. Chapter 3 showed further phenotypic differences in fitness-related traits, with faster growth, more active swimming and lower survival associated with northern stocks. Chapter 4 developed protocols to quantify lumpfish personality and found that bolder individuals interacted more with salmon, whereas, a syndrome for social-aggression was linked to antagonistic behaviour. Patterns of genetic and phenotypic variation imply population differentiation is reflected in stocks commonly used in aquaculture. Common-garden trials suggested translocated lumpfish show reduced fitness, therefore establishing regionally-specific stocks may benefit performance and minimise detriment to wild populations via introgression through farm escapes. Personality constituted a major source of variation in cleaning behaviour, selecting bold lumpfish could optimise efficiency.