Necatoriasis: treatment and developmental therapeutics

Hookworm infection as a model for deepen knowledge of iron metabolism and erythropoiesis in anemia

Over the years, there has been progress in understanding the molecular aspects of iron metabolism and erythropoiesis. However, despite research conducted both in laboratories and living organisms, there are still unanswered questions due to the complex nature of these fields. In this study we investigated the effects of hookworm infection on iron metabolism and how the hosts response to anemia is affected using hamsters infected with Ancylostoma ceylanicum as a model. Our data revealed interesting relationships between infection-induced anemia, erythropoiesis, iron metabolism, and immune modulation, such that the elevated production of erythropoietin (EPO) in renal tissue indicated intensified erythropoiesis in response to anemia. Additionally, the increased expression of the erythroferrone (ERFE) gene in the spleen suggested its involvement in iron regulation and erythropoiesis. Gene expression patterns of genes related to iron metabolism varied in different tissues, indicating tissue-specific adaptations to hypoxia. The modulation of pro-inflammatory and anti-inflammatory cytokines highlighted the delicate balance between immune response and erythropoiesis. Data derived from the investigation of changes induced in iron metabolism and stress erythropoiesis following anemia aid in our understanding of mechanisms related to blood spoliation and anemia, which could potentially be extrapolated or compared to other types or causes of anemia. These findings also contribute to our understanding of the pathophysiology of erythropoiesis in the context of blood loss.

New drugs targeting Th2 lymphocytes in asthma

Asthma represents a profound worldwide public health problem. The most effective anti-asthmatic drugs currently available include inhaled beta2-agonists and glucocorticoids and control asthma in about 90-95% of patients. The current asthma therapies are not cures and symptoms return soon after treatment is stopped even after long term therapy. Although glucocorticoids are highly effective in controlling the inflammatory process in asthma, they appear to have little effect on the lower airway remodelling processes that appear to play a role in the pathophysiology of asthma at currently prescribed doses. The development of novel drugs may allow resolution of these changes. In addition, severe glucocorticoid-dependent and resistant asthma presents a great clinical burden and reducing the side-effects of glucocorticoids using novel steroid-sparing agents is needed. Furthermore, the mechanisms involved in the persistence of inflammation are poorly understood and the reasons why some patients have severe life threatening asthma and others have very mild disease are still unknown. Drug development for asthma has been directed at improving currently available drugs and findings new compounds that usually target the Th2-driven airway inflammatory response. Considering the apparently central role of T lymphocytes in the pathogenesis of asthma, drugs targeting disease-inducing Th2 cells are promising therapeutic strategies. However, although animal models of asthma suggest that this is feasible, the translation of these types of studies for the treatment of human asthma remains poor due to the limitations of the models currently used. The myriad of new compounds that are in development directed to modulate Th2 cells recruitment and/or activation will clarify in the near future the relative importance of these cells and their mediators in the complex interactions with the other pro-inflammatory/anti-inflammatory cells and mediators responsible of the different asthmatic phenotypes. Some of these new Th2-oriented strategies may in the future not only control symptoms and modify the natural course of asthma, but also potentially prevent or cure the disease.

Necator americanus: Optimization of the golden hamster model for testing anthelmintic drugs

Laboratory golden hamsters (Mesocricetus auratus) were infected with Necator americanus under several different parasite and host conditions to optimize the model for testing anthelminthic drugs. The results confirmed that male hamsters were more susceptible to infection than females. Host age in the range of 5-15 weeks was not a factor that impacted on adult worm burden, and similar worm burdens were achieved using doses of 150, 250 or 500 N. americanus L3 (NaL3). The largest numbers of adult hookworms were recovered on days 21-28 post-infection, with a significant decrease at days 40-50 post-infection. Therefore adult worm recovery is maximal approximately 11-18 days prior to patency and host blood loss. From these studies a drug evaluation protocol was developed using 150 NaL3 as the infectious dose and then evaluating the anthelminthic effects of the drugs albendazole, tribendimidine, and pyrantel pamoate on days 21-28 post-infection. The model confirms the anthelminthic activity of albendazole, tribendimidine, and pyrantel pamoate and has the potential as a laboratory animal model to detect emerging drug resistance.

Platelet parameters in subjects infected with hookworm

Hookworm is an important intestinal parasite infection with high prevalence in tropical countries. In addition to iron deficiency anaemia, the human hookworm appears to have evolved a number of complementary strategies to overcome the host's haemostatic processes. These include the inhibition of blood coagulation, platelet aggregation and mediator release, and the secretion of fibrinogenolytic enzymes. In this work, we studied the platelets in the subjects with detection of hookworm infection from screening stool examination comparing to those without. One hundred subjects were included, studied for stool parasite and platelet parameters. Of our 100 subjects, hookworms were identified in stools of six cases, giving an infection rate equal to 6%. The platelet parameters of the subjects showed a statistically significant lowering of mean platelet volume (MPV) in the subjects with hookworm infection. Also, we detected a non-significant lower platelet count in subjects with hookworm infections. Of interest, the alteration in platelet size, identified by platelet parameters, has never been documented in the literature. This observation might be a pathological process or might be an accidental finding in our study.

[Imported hookworm infection in African immigrants in Spain: study of 285 patients]

BACKGROUND AND OBJECTIVE

Hookworm infection is a worldwide intestinal parasitic disease affecting more than one billion people. It represents an important public health problem in rural areas of developing countries. In our environment, it is generally considered an imported disease due to the immigration process.

PATIENTS AND METHOD

Retrospective observational study of African immigrants diagnosed with hookworm infection at the Immigration and Tropical Medicine Unit of the Hospital of Mataró over the period 1984-1999.

RESULTS

We identified 285 patients, mainly young males, from Gambia or Senegal, with a precarious job who had arrived in Spain 3 years earlier or less. Abdominal pain was the commonest reason for consultation (28.8%) cases. Non digestive symptoms were 35.6% and 4.6% remained assymptomatic. 60% had a concomitant infectious disease. Laboratory tests showed iron-deficiency anemia in 28.4% and eosinophilia in 52.3%. 70% of patients did not come to visit after treatment.

CONCLUSIONS

Microbiologic stool examination is recommended as part of the health assessment of immigrants from countries where hookworm infection is highly prevalent, even in the absence of abdominal symptoms or abnormalities of the red and white blood series.