Hepatozoon pyramidumi sp. n. (Apicomplexa: Adeleorina) from the blood of Echis pyramidum: morphology and SSU rDNA sequence / Hepatozoon pyramidumi sp. n. (Apicomplexa: Adeleorina) do sangue de Echis pyramidum: morfologia e sequência de SSU rDNA

Hepatozoon pyramidumi sp. n. is described from the blood of the Egyptian saw-scaled viper, Echis pyramidum, captured from Saudi Arabia. Five out of ten viper specimens examined (50%) were found infected with Hepatozoon pyramidumi sp. n. with parasitaemia level ranged from 20-30%. The infection was restricted only to the erythrocytes. Two morphologically different forms of intraerythrocytic stages were observed; small and mature gamonts. The small ganomt with average size of 10.7 × 3.5 μm. Mature gamont was sausage-shaped with recurved poles measuring 16.3 × 4.2 μm in average size. Infected erythrocytes were hypertrophied; their nuclei were deformed and sometimes displaced from their central position in the normal uninfected cell. Merogonic stages were observed in the lung endothelial cell and the liver parenchyma cells. Mature meront was 17.8 × 13.6 µm and contained banana-shaped merozoites with average size of ~15 × 2 µm. Phylogenetic analysis based on the SSU rDNA sequence clustered Hepatozoon pyramidumi sp. n with previously sequenced Hepatozoon spp., most of them infected reptilian hosts without geographic consideration. The morphological and molecular comparison with closely related species proved the taxonomic uniqueness and novelty of the present form.(AU)

Hepatozoon pyramidumi sp. n. é descrito a partir do sangue da víbora em escamas e quilhas serrilhadas, Echis pyramidum, capturada na Arábia Saudita. Cinco de dez espécimes de víbora examinadas (50%) foram encontradas infectadas com Hepatozoon pyramidumi sp. n. com nível de parasitemia de 20% a 30%. A infecção foi restrita apenas aos eritrócitos. Foram observadas duas formas morfologicamente diferentes de estágios intra-eritrocíticos: gamontes de tamanho pequeno e madura. As formas menores de gamontes apresentaram média de 10,7 × 3,5 μm. Os gamontes maduros apresentaram forma de salsicha, com pequenos polos recurvados, medindo 16,3 × 4,2 μm, em média. Os eritrócitos infectados estavam aumentados de tamanho; seus núcleos encontravam-se deformados e, algumas vezes, deslocados de sua posição central, quando comparados às células normais não-infectadas. Foram observados estágios merogônicos em células endoteliais pulmonares e nas células do parênquima hepático. Os merontes maduros apresentavam 17,8 × 13,6 µm e continham merozoítos em forma de banana com tamanho médio de ~ 15 × 2 µm. A análise filogenética baseada nas sequências SSU rDNA agrupou Hepatozoon pyramidumi sp. n com Hepatozoon spp. detectados em répteis de várias regiões geográficas. Por meio de análises morfológicas e moleculares com espécies intimamente relacionadas, demonstrou-se a singularidade dessa nova espécie de Hepatozoon.(AU)

Delayed double reading of whole blood clotting test (WBCT) results at 20 and 30 minutes enhances diagnosis and treatment of viper evenomation

The whole blood clotting test (WBCT) is a simple test of coagulation that is often used in the assessment, diagnosis, and therapeutic monitoring of snakebite patients in sub-Saharan Africa. WBCT requires only a clean glass tube and several milliliters of venous blood and is ideal for use in poorly equipped health centers throughout the rural areas where 95% of snakebites occur. However, questions surrounding the accuracy and reliability of the test remain unanswered due to variations in testing conditions and a lack of comparative research with which to validate them. This is the first study to evaluate WBCT results at both 20-min (WBCT20) and 30-min (WBCT30) reading times in the same group of snakebite patients. Methods In order to define the best reading time, the authors compared the results of serial WBCT evaluation at both 20 and 30 min after collection in 23 patients treated for snake envenomation in Bembèrèkè, northern Benin. Results WBCT results were identical at both reading times in patients without coagulopathy or when coagulation was restored permanently following a single dose of antivenom. Out of 17 patients with coagulopathy, 14 showed discrepancies between WBCT20 and WBCT30 results in at least one pair of serial evaluations. These could be completely contradictory results (e.g. normal clot at WBCT20 and no clot at WBCT30) or a marked difference in the quality of the clot (e.g. no clotting activity at WBCT20 and an unstable partial clot at WBCT30)...(AU)

Delayed double reading of whole blood clotting test (WBCT) results at 20 and 30 minutes enhances diagnosis and treatment of viper evenomation

The whole blood clotting test (WBCT) is a simple test of coagulation that is often used in the assessment, diagnosis, and therapeutic monitoring of snakebite patients in sub-Saharan Africa. WBCT requires only a clean glass tube and several milliliters of venous blood and is ideal for use in poorly equipped health centers throughout the rural areas where 95% of snakebites occur. However, questions surrounding the accuracy and reliability of the test remain unanswered due to variations in testing conditions and a lack of comparative research with which to validate them. This is the first study to evaluate WBCT results at both 20-min (WBCT20) and 30-min (WBCT30) reading times in the same group of snakebite patients. Methods In order to define the best reading time, the authors compared the results of serial WBCT evaluation at both 20 and 30 min after collection in 23 patients treated for snake envenomation in Bembèrèkè, northern Benin. Results WBCT results were identical at both reading times in patients without coagulopathy or when coagulation was restored permanently following a single dose of antivenom. Out of 17 patients with coagulopathy, 14 showed discrepancies between WBCT20 and WBCT30 results in at least one pair of serial evaluations. These could be completely contradictory results (e.g. normal clot at WBCT20 and no clot at WBCT30) or a marked difference in the quality of the clot (e.g. no clotting activity at WBCT20 and an unstable partial clot at WBCT30)...

Public health aspects of snakebite care in West Africa: perspectives from Nigeria

Snakebite envenoming is a major public health problem among rural communities of the Nigerian savanna. The saw-scaled or carpet viper (Echis ocellatus) and, to a lesser extent, the African cobras (Naja spp.) and puff adders (Bitis arietans) have proved to be the most important cause of mortality and morbidity. The main clinical features of E. ocellatus envenoming are systemic hemorrhage, incoagulable blood, shock, local swelling, bleeding and, occasionally, necrosis. Bites may be complicated by amputation, blindness, disability, disfigurement, mutilation, tissue destruction and psychological consequences. Antivenom remains the hallmark and mainstay of envenoming management while studies in Nigeria confirm its protection of over 80% against mortality from carpet-viper bites. However, the availability, distribution and utilization of antivenom remain challenging although two new antivenoms (monospecific EchiTab G and trispecific EchiTab ICP-Plus) derived from Nigerian snake venoms have proven very effective and safe in clinical trials. A hub-and-spoke strategy is suggested for broadening antivenom access to endemic rural areas together with instituting quality assurance, standardization and manpower training. With the advent of antivenomics, national health authorities must be aided in selecting and purchasing antivenoms appropriate to their national needs while manufacturers should be helped in practical ways to improve the safety, efficacy and potential coverage against snake venoms and pricing of their products.

Public health aspects of snakebite care in West Africa: perspectives from Nigeria

Snakebite envenoming is a major public health problem among rural communities of the Nigerian savanna. The saw-scaled or carpet viper (Echis ocellatus) and, to a lesser extent, the African cobras (Naja spp.) and puff adders (Bitis arietans) have proved to be the most important cause of mortality and morbidity. The main clinical features of E. ocellatus envenoming are systemic hemorrhage, incoagulable blood, shock, local swelling, bleeding and, occasionally, necrosis. Bites may be complicated by amputation, blindness, disability, disfigurement, mutilation, tissue destruction and psychological consequences. Antivenom remains the hallmark and mainstay of envenoming management while studies in Nigeria confirm its protection of over 80% against mortality from carpet-viper bites. However, the availability, distribution and utilization of antivenom remain challenging although two new antivenoms (monospecific EchiTab G and trispecific EchiTab ICP-Plus) derived from Nigerian snake venoms have proven very effective and safe in clinical trials. A hub-and-spoke strategy is suggested for broadening antivenom access to endemic rural areas together with instituting quality assurance, standardization and manpower training. With the advent of antivenomics, national health authorities must be aided in selecting and purchasing antivenoms appropriate to their national needs while manufacturers should be helped in practical ways to improve the safety, efficacy and potential coverage against snake venoms and pricing of their products.

Public health aspects of snakebite care in West Africa: perspectives from Nigeria

Snakebite envenoming is a major public health problem among rural communities of the Nigerian savanna. The saw-scaled or carpet viper (Echis ocellatus) and, to a lesser extent, the African cobras (Naja spp.) and puff adders (Bitis arietans) have proved to be the most important cause of mortality and morbidity. The main clinical features of E. ocellatus envenoming are systemic hemorrhage, incoagulable blood, shock, local swelling, bleeding and, occasionally, necrosis. Bites may be complicated by amputation, blindness, disability, disfigurement, mutilation, tissue destruction and psychological consequences. Antivenom remains the hallmark and mainstay of envenoming management while studies in Nigeria confirm its protection of over 80% against mortality from carpet-viper bites. However, the availability, distribution and utilization of antivenom remain challenging although two new antivenoms (monospecific EchiTab G and trispecific EchiTab ICP-Plus) derived from Nigerian snake venoms have proven very effective and safe in clinical trials. A hub-and-spoke strategy is suggested for broadening antivenom access to endemic rural areas together with instituting quality assurance, standardization and manpower training. With the advent of antivenomics, national health authorities must be aided in selecting and purchasing antivenoms appropriate to their national needs while manufacturers should be helped in practical ways to improve the safety, efficacy and potential coverage against snake venoms and pricing of their products.(AU)

In vivo evaluation of homeostatic effects of Echis carinatus snake venom in Iran

The venom of the family Viperidae, including the saw-scaled viper, is rich in serine proteinases and metalloproteinases, which affect the nervous system, complementary system, blood coagulation, platelet aggregation and blood pressure. One of the most prominent effects of the snake venom of Echis carinatus (Ec) is its coagulation activity, used for killing prey. Materials and methods Subfractions F1A and F1B were isolated from Ec crude venom by a combination of gel chromatography (Sephadex G-75) and ion exchange chromatography on a DEAE-Sepharose (DE-52). These subfractions were then intravenously (IV) injected into NIH male mice. Blood samples were taken before and after the administration of these subfractions. Times for prothrombin, partial thromboplastin and fibrinogen were recorded. Results and conclusions Comparison of the prothrombin time before and after F1A and F1B administrations showed that time for blood coagulation after injection is shorter than that of normal blood coagulation and also reduced coagulation time after Ec crude venom injection. This difference in coagulation time shows the intense coagulation activity of these subfractions that significantly increase the coagulation cascade rate and Causes to quick blood coagulation. The LD50 of the Ec crude venom was also determined to be 11.1 μg/mouse. Different crude venom doses were prepared with physiological serum and injected into four mice. Comparison of the prothrombin times after injection of subfractions F1A and F1B showed that the rate of mouse blood coagulation increases considerably. Comparing the partial thromboplastin times after injecting these subfractions with this normal test time showed that the activity rate of intrinsic blood coagulation system rose sharply in mice. Finally, by comparing the fibrinogen time after subfraction injections and normal test time, we can.AU)

In vivo evaluation of homeostatic effects of Echis carinatus snake venom in Iran

The venom of the family Viperidae, including the saw-scaled viper, is rich in serine proteinases and metalloproteinases, which affect the nervous system, complementary system, blood coagulation, platelet aggregation and blood pressure. One of the most prominent effects of the snake venom of Echis carinatus (Ec) is its coagulation activity, used for killing prey. Materials and methods Subfractions F1A and F1B were isolated from Ec crude venom by a combination of gel chromatography (Sephadex G-75) and ion exchange chromatography on a DEAE-Sepharose (DE-52). These subfractions were then intravenously (IV) injected into NIH male mice. Blood samples were taken before and after the administration of these subfractions. Times for prothrombin, partial thromboplastin and fibrinogen were recorded. Results and conclusions Comparison of the prothrombin time before and after F1A and F1B administrations showed that time for blood coagulation after injection is shorter than that of normal blood coagulation and also reduced coagulation time after Ec crude venom injection. This difference in coagulation time shows the intense coagulation activity of these subfractions that significantly increase the coagulation cascade rate and Causes to quick blood coagulation. The LD50 of the Ec crude venom was also determined to be 11.1 μg/mouse. Different crude venom doses were prepared with physiological serum and injected into four mice. Comparison of the prothrombin times after injection of subfractions F1A and F1B showed that the rate of mouse blood coagulation increases considerably. Comparing the partial thromboplastin times after injecting these subfractions with this normal test time showed that the activity rate of intrinsic blood coagulation system rose sharply in mice. Finally, by comparing the fibrinogen time after subfraction injections and normal test time, we can.

Toxicity and symptomatic identification of species involved in snakebites in the Indian subcontinent

Snakebites, being the major occupational hazard for farm workers, claim a large number of lives in the Indian subcontinent. During the course of medical management, identification of the biting species is given a low priority, resorting to prescription of polyvalent anti-snake venom. Whereas the World Health Organization (WHO) recommends monospecific anti-snake venom instead of polyvalent anti-snake venom. Thus, it is essential to identify the aggressor species either by a visual inspection or by the symptoms of the victim. Along with the four deadly venomous species (cobra, krait, Russell's viper, and saw-scaled viper), there are a number of other species of medical importance, whose venoms and bites have not been paid much attention. Thus, a misclassification resulting into erroneous treatment cannot be ruled out. This paper discusses the nature, constitution, and toxicity of venoms and their possible toxic effects on victims of snakebites. An attempt has also been made to categorize the distinctive symptoms due to the bites of the four major venomous species and their severity grading.

Toxicity and symptomatic identification of species involved in snakebites in the Indian subcontinent

Snakebites, being the major occupational hazard for farm workers, claim a large number of lives in the Indian subcontinent. During the course of medical management, identification of the biting species is given a low priority, resorting to prescription of polyvalent anti-snake venom. Whereas the World Health Organization (WHO) recommends monospecific anti-snake venom instead of polyvalent anti-snake venom. Thus, it is essential to identify the aggressor species either by a visual inspection or by the symptoms of the victim. Along with the four deadly venomous species (cobra, krait, Russell's viper, and saw-scaled viper), there are a number of other species of medical importance, whose venoms and bites have not been paid much attention. Thus, a misclassification resulting into erroneous treatment cannot be ruled out. This paper discusses the nature, constitution, and toxicity of venoms and their possible toxic effects on victims of snakebites. An attempt has also been made to categorize the distinctive symptoms due to the bites of the four major venomous species and their severity grading.(AU)

Central retinal artery occlusion: an unusual complication of snakebite

Snakebites are endemic in some parts of India, being associated with a number of complications. Ocular disturbances are rare, except for injury to the cornea or conjunctiva when the eye is directly exposed to the venom. In this work, we present a case of central retinal artery occlusion caused by snakebite.

Central retinal artery occlusion: an unusual complication of snakebite

Snakebites are endemic in some parts of India, being associated with a number of complications. Ocular disturbances are rare, except for injury to the cornea or conjunctiva when the eye is directly exposed to the venom. In this work, we present a case of central retinal artery occlusion caused by snakebite.(AU)