Snakes and snake bite in Nepal

At Nepal's northern border with Tibet is the great Himalaya Range. capped by Mount Everest itself (8848 ni) and including four of the other eight highest mountains in the world. South of the Kathmandu Valley at the centre of the country are the lesser mountains of the Mahabharat Range and Churia Ghati Hills. below 3000 m, and in the far south, stretching to India. are the fertile alluvial Terai Plains with scattered swamps and hardwood and bamboo forests. The distribution of the 14 species of venomous snakes known to inhabit Nepal is determined by geography and climate. The range of only one species. the Himalayan pit viper (Agkistrotlori hir~itilri~tiiiu.s), extends into the higher elevations.Published versio

Randomised Controlled Double-Blind Non-Inferiority Trial of Two Antivenoms for Saw-Scaled or Carpet Viper (Echis ocellatus) Envenoming in Nigeria

Snake bite threatens millions of poor rural folk throughout Africa. In Nigeria, as in many countries of sub-Saharan Africa, it takes a terrible toll on human life and limb. Over the years, the news for those exposed to snake bite has been generally bad: withdrawal of antivenom manufacturers, increasing cost and, most recently, the marketing of ineffective or fake antivenoms in the region. Our paper reports encouraging results achieved by two antivenoms created as a direct consequence of the present crisis in antivenom supply for Africa. They have been assessed in the most powerful trial ever attempted in this field. The trial showed that in people with non-clotting blood following carpet viper bite, the commonest cause of snake bite morbidity and mortality in the West African savannah, administration of the antivenoms- EchiTAb G and EchiTAb Plus-ICP led to permanent restoration of blood clotting in 76% and 83% of the patients within 6 hours, respectively. Generally mild early adverse reactions were recorded in 19% and 26%, respectively. Both antivenoms proved effective and acceptably safe and can be recommended for treating carpet viper envenoming in Nigeria

Snake bite mimicking brain death

A 6 year old girl woke up with pain and increasing swelling over the left hand and difficulty in breathing. On examination, she had swelling of the left forearm and hand, flaccid quadriparesis and was in respiratory failure requiring mechanical ventilation. Two clean puncture wounds were identified on the left thumb. A provisional diagnosis of snake bite with severe envenomation was made and she was given anti snake venom therapy. Over a period of about 4 hours her weakness progressed. She became areflexic, developed internal and external ophthalmoplegia and loss of other brain stem reflexes mimicking brain death. Mechanical ventilation was continued despite features suggestive of brain stem dysfunction. About 36 hours after ventilation she showed a flicker of movement of her fingers and gradually the power improved. She was weaned off the ventilator and extubated after 5 days. External ophthalmoplegia is an established association with cobra envenomation, but, this combination of internal and external ophthalmoplegia can mimic brain death and pose a dilemma to the caregivers regarding continuation of therapy

Plasmodium falciparum: inhibition/reversal of cytoadherence of Thai isolates to melanoma cells by local immune sera

The effect of sera on the cytoadherence in vitro of Plasmodium falciparum-infected erythrocytes to melanoma cells was examined. Sera from 19 healthy individuals living in endemic malarious areas in Thailand and 24 patients with P. falciparum malaria were tested against four local P. falciparum isolates. Out of 57 sera examined, 12 (21 %) showed significant inhibition (> 50%) of cytoadherence for at least one isolate. Anti-malarial IgG antibody titres were determined for all 57 sera and although 11 of the 12 inhibitory sera had relatively high titres, 36 out of47 sera with similarly high titres showed no significant inhibitory activity. Convalescent sera were no more effective than corresponding acute sera in inhibiting the cytoadherence of erythrocytes infected with any of the four heterologous isolates examined. Sera which significantly inhibited cytoadherence were also capable of reversing cytoadherence, and pooled plasma, from healthy individuals living in malarious areas, was effective in significantly reversing the in vitro cytoadherence of all the five parasite isolates examined. The results confirm the antibody mediated strain-specific nature of the inhibition of cytoadherence and stress the difficulty in selecting immune sera potentially useful for the immunotherapy of cerebral malaria patients in Thailand

Snake Envenoming: A Disease of Poverty

Every year snake envenoming kills more people in the tropics than some of the world's recognised neglected tropical diseases (NTDs), including schistosomiasis and leishmaniasis. While lacking the epidemic potential of an infectious/vector-borne disease, snake envenoming in rural tropical communities has as great a medical mortality, if not morbidity, as the NTDs. The recent categorisation of snake envenoming as an NTD is an important advance that hopefully will result in the wider recognition and allocation of resources, particularly since death from snake envenoming is preventable; antivenom is very effective when the appropriate antivenom is correctly administered. Snake envenoming urgently requires international support to instigate the epidemiological, health education, and effective treatment initiatives that proved so potent in addressing the medical burden of NTDs such as leprosy and dracunculosis. All the global estimates of snake envenoming and deaths from snakebite indicate that mortality is highest in the world's tropical countries. Here we examined associations between the globally available data on (i) snakebite-induced mortality and (ii) socioeconomic markers of poverty. Our data unequivocally establishes that snake envenoming is globally associated with poverty, a distinctive characteristic of the neglected tropical diseases

Inhibition of Hemorragic Snake Venom Components: Old and New Approaches

Snake venoms are complex toxin mixtures. Viperidae and Crotalidae venoms, which are hemotoxic, are responsible for most of the envenomations around the world. Administration of antivenins aimed at the neutralization of toxins in humans is prone to potential risks. Neutralization of snake venom toxins has been achieved through different approaches: plant extracts have been utilized in etnomedicine. Direct electric current from low voltage showed neutralizing properties against venom phospholipase A2 and metalloproteases. This mini-review summarizes new achievements in venom key component inhibition. A deeper knowledge of alternative ways to inhibit venom toxins may provide supplemental treatments to serum therapy

Unexpectedly long incubation period of Plasmodium vivax malaria, in the absence of chemoprophylaxis, in patients diagnosed outside the transmission area in Brazil

<p>Abstract</p> <p>Background</p> <p>In 2010, Brazil recorded 3343,599 cases of malaria, with 99.6% of them concentrated in the Amazon region. <it>Plasmodium vivax </it>accounts for 86% of the cases circulating in the country. The extra-Amazonian region, where transmission does not occur, recorded about 566 cases imported from the Amazonian area in Brazil and South America, from Central America, Asia and African countries. Prolonged incubation periods have been described for <it>P. vivax </it>malaria in temperate climates. The diversity in essential biological characteristics is traditionally considered as one possible explanation to the emergence of relapse in malaria and to the differences in the duration of the incubation period, which can also be explained by the use of chemoprophylaxis. Studying the reported cases of <it>P. vivax </it>malaria in Rio de Janeiro, where there is no vector transmission, has made it possible to evaluate the extension of the incubation period and to notice that it may be extended in some cases.</p> <p>Methods</p> <p>Descriptive study of every malaria patients who visited the clinic in the last five years. The mean, standard deviation, median, minimum and maximum of all incubation periods were analysed.</p> <p>Results</p> <p>From the total of 80 patients seen in the clinic during the study time, with confirmed diagnosis of malaria, 49 (63%) were infected with <it>P. vivax</it>. Between those, seven had an estimated incubation period varying from three to 12 months and were returned travellers from Brazilian Amazonian states (6) and Indonesia (1). None of them had taken malarial chemoprophylaxis.</p> <p>Conclusions</p> <p>The authors emphasize that considering malaria as a possible cause of febrile syndrome should be a post-travel routine, independent of the time elapsed after exposure in the transmission area, even in the absence of malaria chemoprophylaxis. They speculate that, since there is no current and detailed information about the biological cycle of human malaria plasmodia's in Brazil, it is possible that new strains are circulating in endemic regions or a change in cycle of preexisting strains is occurring. Considering that a prolonged incubation period may confer advantages on the survival of the parasite, difficulties in malaria control might arise.</p

3D flow in the venom channel of a spitting cobra: do the ridges in the fangs act as fluid guide vanes?

The spitting cobra Naja pallida can eject its venom towards an offender from a distance of up to two meters. The aim of this study was to understand the mechanisms responsible for the relatively large distance covered by the venom jet although the venom channel is only of micro-scale. Therefore, we analysed factors that influence secondary flow and pressure drop in the venom channel, which include the physical-chemical properties of venom liquid and the morphology of the venom channel. The cobra venom showed shear-reducing properties and the venom channel had paired ridges that span from the last third of the channel to its distal end, terminating laterally and in close proximity to the discharge orifice. To analyze the functional significance of these ridges we generated a numerical and an experimental model of the venom channel. Computational fluid dynamics (CFD) and Particle-Image Velocimetry (PIV) revealed that the paired interior ridges shape the flow structure upstream of the sharp 90° bend at the distal end. The occurrence of secondary flow structures resembling Dean-type vortical structures in the venom channel can be observed, which induce additional pressure loss. Comparing a venom channel featuring ridges with an identical channel featuring no ridges, one can observe a reduction of pressure loss of about 30%. Therefore it is concluded that the function of the ridges is similar to guide vanes used by engineers to reduce pressure loss in curved flow channels

Snakebite Mortality in India: A Nationally Representative Mortality Survey

Earlier hospital based reports estimate about 1,300 to 50,000 annual deaths from snakebites per year in India. Here, we present the first ever direct estimates from a national mortality survey of 1.1 million homes in 2001–03. Full-time, non-medical field workers interviewed living respondents about all deaths. The underlying causes were independently coded by two of 130 trained physicians. The study found 562 deaths (0.47% of total deaths) were assigned to snakebites, mostly in rural areas, and more commonly among males than females and peaking at ages 15–29. Snakebites also occurred more often during the rainy monsoon season. This proportion represents about 45,900 annual snakebite deaths nationally (99% CI 40,900 to 50,900) or an annual age-standardised rate of 4.1/100,000 (99% CI 3.6–4.5), with higher rates in rural areas (5.4) and with the highest rate in the state of Andhra Pradesh (6.2). Annual snakebite deaths were greatest in the states of Uttar Pradesh (8,700), Andhra Pradesh (5,200), and Bihar (4,500). Thus, snakebite remains an underestimated cause of accidental death in modern India, causing about one death for every two HIV-related deaths. Because a large proportion of global totals of snakebites arise from India, global snakebite totals might also be underestimated. Effective interventions involving education and antivenom provision would reduce snakebite deaths in India