Immune-mediated hookworm clearance and survival of a marine mammal decrease with warmer ocean temperatures.

Increases in ocean temperature are associated with changes in the distribution of fish stocks, and the foraging regimes and maternal attendance patterns of marine mammals. However, it is not well understood how these changes affect offspring health and survival. The maternal attendance patterns and immunity of South American fur seals were assessed in a rookery where hookworm disease is the main cause of pup mortality. Pups receiving higher levels of maternal attendance had a positive energy balance and a more reactive immune system. These pups were able to expel hookworms through a specific immune mediated mechanism and survived the infection. Maternal attendance was higher in years with low sea surface temperature, therefore, the mean hookworm burden and mortality increased with sea surface temperature over a 10-year period. We provide a mechanistic explanation regarding how changes in ocean temperature and maternal care affect infectious diseases dynamics in a marine mammal.

Epidemiology and morbidity of hookworm-related cutaneous larva migrans (HrCLM): Results of a cohort study over a period of six months in a resource-poor community in Manaus, Brazil.

BACKGROUND: Hookworm-related cutaneous larva migrans (HrCLM) is a neglected parasitic skin disease, widespread in resource-poor communities in tropical and subtropical countries. Incidence and risk factors have never been investigated in a cohort study. METHODOLOGY/PRINCIPAL FINDINGS: To understand the seasonal epidemiology of HrCLM, an open cohort of 476 children in a resource-poor community in Manaus, Brazil was examined for HrCLM monthly over a period of 6 months. Monthly prevalence and intensity of infection were correlated with the amount of monthly precipitation. Multivariable Cox regression analysis indicated male sex (hazard ratio [HR] 3.29; 95% confidence interval [CI] 1.95-5.56), walking barefoot on sandy ground (HR 2.30; 95% CI 1.03-5.16), poverty (HR 2.13; 95% CI 1.09-4.17) and age between 10 and 14 years (HR 1.87; 95% CI 1.01-3.46) as predictors of HrCLM. Monthly incidence rates ranged between 0.21 and 1.05 cases per person-year with an overall incidence of 0.52 per person-year. CONCLUSIONS/SIGNIFICANCE: HrCLM is a frequent parasitic skin disease in this resource-poor community. Every second child theoretically becomes infected during one year. Boys, 10 to 14 years old, belonging to the poorest households of the community, are the most vulnerable population group. Even in the tropical monsoonal climate of Amazonia there is a considerable seasonal variation with monthly incidence and number of lesions peaking in the rainy season.

Hookworm Infection in South American Fur Seal ( Arctocephalus australis) Pups.

Tissues of South American fur seal pups naturally infected with hookworms ( Uncinaria sp) were examined. Hookworm infection was found in nearly all pups examined (132/140, 94%), and hookworm enteritis with secondary bacteremia was considered the cause of death in 46 (35%) pups. Common findings in these pups included severe hemorrhagic enteritis and numerous (mean intensity = 761.8) hookworms in the jejunum. Hookworms were recovered from the abdominal cavity in 12 of 55 pups (22%) examined through peritoneal wash; these pups had an average of 1343.3 intestinal hookworms and marked fibrinohemorrhagic peritonitis. In all pups that died as a consequence of hookworm infection, the intestinal villi were short, blunt, and fused, and there were variable numbers of free and intrahistiocytic gram-negative bacteria in submucosal hookworm feeding tracks, mesenteric lymph nodes, spleen, blood vessels, and liver sinusoids. Pups that died of causes unrelated to the hookworm infection (trauma) had hookworm feeding tracks confined to the apical portions of the mucosa, and moderate to marked catarrhal eosinophilic enteritis. The number of hookworms was negatively correlated with intestinal villous length and number of leukocytes in the intestine. Pups with hookworm peritoneal penetration had nematodes with little or no blood in the hookworm intestine, suggesting that lack of food for the nematode could be associated with peritoneal penetration. Findings suggest that the initial burden of larval infection, the level of the host tissue response, or a combination determine the number of nematodes in the intestine, the severity of hookworm tissue damage, and pup mortality.

Epidemiology of soil-transmitted helminthiases-related mortality in Brazil.

Soil-transmitted helminth (STH) infections are widely distributed in tropical and subtropical areas, including Brazil. We performed a nationwide population-based study including all deaths in Brazil from 2000 to 2011, in which STHs (ascariasis, trichuriasis and/or hookworm infection) were mentioned on death certificates, either as underlying or as associated causes of death. Epidemiological characteristics, time trends and spatial analysis of STH-related mortality were analysed. STHs was identified on 853/12 491 280 death certificates: 827 (97·0%) deaths related to ascariasis, 25 (2·9%) to hookworm infections, and 1 (0·1%) to trichuriasis. The average annual age-adjusted mortality rate was 0·34/1 000 000 inhabitants (95% confidence interval: 0·27-0·44). Females, children <10 years of age, indigenous ethnic groups and residents in the Northeast region had highest STH-related mortality rates. Nationwide mortality decreased significantly over time (annual percent change: -5·7%; 95% CI: -6·9 to -4·4), with regional differences. We identified spatial high-risk clusters for STH-related mortality mainly in the North, Northeast and South regions. Diseases of the digestive system and infectious/parasitic diseases were the most commonly associated causes of death mentioned in the STH-related deaths. Despite decreasing mortality in Brazil, a considerable number of deaths is caused by STHs, with ascariasis responsible for the vast majority. There were marked regional differences, affecting mainly children and vulnerable populations.

Hookworm enteritis with bacteremia in California sea lion pups on San Miguel Island.

Large breeding populations of California sea lions (Zalophus californianus) are located on San Miguel and San Nicolas Islands in the Southern California Bight. In 2001, there was a substantial increase in pup mortality in late summer and fall. From June 2002 to January 2003, 208 freshly dead pups were examined on San Miguel Island, the most western of the Channel Islands off the coast of southern California. Tissues from 186 of these pups were examined histologically. The primary lesions in 133 (72%) of the pups were an enteritis associated with hookworms and infections in major organs. Emaciation/starvation in 43 pups (26%) was the second most important cause of death.

Some contributions from the doctor of the miners in the Simplon tunnel: The most human of victories. The Provinces of Italy to the Simplon tunnel. The family of the miner at Simplon. 1906.

Similarly to Daniele Pometta (1869-1949) on the northern front, Giuseppe Volante (1870-1936) from Turin, a valid clinician and hygiene expert was the field doctor for the firm of Brandt, Brandau e C., on the southern part of the Simplon tunnel for the whole period of its excavation (1898-1906). He meticulously organised and carried out with determination the main mission entrusted him which was to prevent the hookworm epidemic which a mere twenty years earlier had cast its shadow over the St. Gotthard tunnel. Volante also authoritatively directed the first aid post and the hospital that the company built at Nante. Evidence of Volante's vast medical experience was seen in the scientific works he published as well as in a report published in the acts of the International Conference on Work-related Illnesses (Volante, 1906a) and then in a comunication at No. 3 Italian Congress on Work-related Illnesses in Turin (Volante, 1911). There are three interesting works reproduced here (Volante, 1906b-c-d) which are substantially aimed at a broad readership and which clearly illustrate the work carried out, the experience gained and also the author's cultural background. Volante's remarks and the data he supplies are "official" but show no sign of partiality; they convey the grandness of the work he contributed towards creating and in some ways also the "generosity" of the company towards the labour force who "only" went on strike three times for better pay, fewer hours and improved working conditions. Volante's opinion on the low morbidity and mortality of the workers is certainly motivated although it is still relative, first and foremost because he had the tragedy of the St Gotthard as a yardstick, but also because it was swayed by the idea, widespread at the time, of fatalism about the potentially negative effects of the type of work. During the International Conference in 1906 Violante was awarded a gold medal for the work he had conducted, and for three years afterwards he worked under Luigi Devoto (1864-1936) in Milan. After that, he returned to his native Turin where he practised urology. According to his direct descendents, he died aged 64 from respiratory insufficiency the causes of which included a "pneumoconiosis" diagnosed by Prof. Quarelli (1881-1954), a renowned doctor of work-related illnesses, which he had obviously contracted in the period when he had been the doctor of the miners (Gius Volante, 2006).

Contrasting effects of heterozygosity on survival and hookworm resistance in California sea lion pups.

Low genetic heterozygosity is associated with loss of fitness in many natural populations. However, it remains unclear whether the mechanism is related to general (i.e. inbreeding) or local effects, in particular from a subset of loci lying close to genes under balancing selection. Here we analyse involving heterozygosity-fitness correlations on neonatal survival of California sea lions and on susceptibility to hookworm (Uncinaria spp.) infection, the single most important cause of pup mortality. We show that regardless of differences in hookworm burden, homozygosity is a key predictor of hookworm-related lesions, with no single locus contributing disproportionately. Conversely, the subsequent occurrence of anaemia due to blood loss in infected pups is overwhelmingly associated with homozygosity at one particular locus, all other loci showing no pattern. Our results suggest contrasting genetic mechanisms underlying two pathologies related to the same pathogen. First, relatively inbred pups are less able to expel hookworms and prevent their attachment to the intestinal mucosa, possibly due to a weakened immune response. In contrast, infected pups that are homozygous for a gene near to microsatellite Hg4.2 are strongly predisposed to anaemia. As yet, this gene is unknown, but could plausibly be involved in the blood-coagulation cascade. Taken together, these results suggest that pathogenic burden alone may not be the main factor regulating pathogen-related mortality in natural populations. Our study could have important implications for the conservation of small, isolated or threatened populations, particularly when they are at a risk of facing pathogenic challenges.

The application of a quantitative approach to the assessment of the relative importance of vector and soil transmitted diseases in Ghana.

The vector and soil transmitted parasitic infections produce a highly diverse group of diseases in terms of the importance of their impact upon human populations and in terms of the control methods that might limit that impact. In Ghana a method was developed for quantitatively assessing the relative importance of different disease problems by estimating the amount of healthy life lost through illness, disability and death as a result of each disease. The quantitative assessment is derived from information on incidence rate, case fatality rate and the extent and duration of disability produced by the disease. The method may be used to help decide the priorities for the allocation of resources to alternative procedures or programmes by calculating the amount of healthy days of life which may be saved by different approaches and then relating these savings to the costs of the approaches. Each of the vector and soil transmitted parasitic diseases in Ghana had special characteristics that influenced the estimates of their relative importance. Attribution of death due to malaria posed special problems, but even with the most conservative estimate malaria was the single most important cause of loss of healthy life of all diseases in Ghana. For schistosomiasis there is such great uncertainty concerning how much disability or mortality that results from infection that the relative importance of schistosomiasis could not be usefully estimated; thus research into the extent of disability and death caused by schistosomiasis should have a very high priority if rational allocation of resources for its control is to be achieved. Onchocerciasis, though not generally considered an important cause of mortality, is an important cause of chronic severe disability. The importance of ascariasis and hookworm remain uncertain both because of the lack of information as to the extent of disability and mortality that they produce and the lack of data in Ghana as to their prevalence and intensity of infection. Guinea worm was of little importance from the national point of view, but was highly important in focal areas. Trypanosomiasis would appear to be of minor importance because its incidence was quite low, but for an epidemic disease such as trypanosomiasis the importance must be estimated based on what would occur if there were not effective surveillance and control methods. Diverse though this group of parasitic diseases is a common thesis is that each has been relatively neglected in relation to its importance and for each a considerable reduction in loss of healthy life should be achievable at reasonable cost.