COVID-19 impacts on healthcare access in sub-Saharan Africa: an overview.

This overview aimed to describe the situation of healthcare access in sub-Saharan Africa, excluding South Africa, during the COVID-19 pandemic. A PubMed® search from March 31, 2020, to August 15, 2022, selected 116 articles. Healthcare access and consequences of COVID-19 were assessed based on comparisons with months before its onset or an identical season in previous years. A general reduction of healthcare delivery, associated with the decline of care quality, and closure of many specialty services were reported. The impact was heterogeneous in space and time, with an increase in urban areas at the beginning of the pandemic (March-June 2020). The return to normalcy was gradual from the 3rd quarter of 2020 until the end of 2021. The impact of COVID-19 on the health system and its use was attributed to (a) conjunctural factors resulting from government actions to mitigate the spread of the epidemic (containment, transportation restrictions, closures of businesses, and places of entertainment or worship); (b) structural factors related to the disruption of public and private facilities and institutions, in particular, the health system; and (c) individual factors linked to the increase in costs, impoverishment of the population, and fear of contamination or stigmatization, which discouraged patients from going to health centers. They have caused considerable socio-economic damage. Several studies emphasized some adaptability of the healthcare offer and resilience of the healthcare system, despite its unpreparedness, which explained a return to normal activities as early as 2022 while the COVID-19 epidemic persisted. There appears to be a strong disproportion between the moderate incidence and severity of COVID-19 in sub-Saharan Africa, and the dramatic impact on healthcare access. Several articles make recommendations for lowering the socioeconomic consequences of future epidemics to ensure better management of health issues.

COVID-19 impacts on healthcare access in sub-Saharan Africa: an overview

Abstract This overview aimed to describe the situation of healthcare access in sub-Saharan Africa, excluding South Africa, during the COVID-19 pandemic. A PubMed® search from March 31, 2020, to August 15, 2022, selected 116 articles. Healthcare access and consequences of COVID-19 were assessed based on comparisons with months before its onset or an identical season in previous years. A general reduction of healthcare delivery, associated with the decline of care quality, and closure of many specialty services were reported. The impact was heterogeneous in space and time, with an increase in urban areas at the beginning of the pandemic (March-June 2020). The return to normalcy was gradual from the 3rd quarter of 2020 until the end of 2021. The impact of COVID-19 on the health system and its use was attributed to (a) conjunctural factors resulting from government actions to mitigate the spread of the epidemic (containment, transportation restrictions, closures of businesses, and places of entertainment or worship); (b) structural factors related to the disruption of public and private facilities and institutions, in particular, the health system; and (c) individual factors linked to the increase in costs, impoverishment of the population, and fear of contamination or stigmatization, which discouraged patients from going to health centers. They have caused considerable socio-economic damage. Several studies emphasized some adaptability of the healthcare offer and resilience of the healthcare system, despite its unpreparedness, which explained a return to normal activities as early as 2022 while the COVID-19 epidemic persisted. There appears to be a strong disproportion between the moderate incidence and severity of COVID-19 in sub-Saharan Africa, and the dramatic impact on healthcare access. Several articles make recommendations for lowering the socioeconomic consequences of future epidemics to ensure better management of health issues.

First reports of envenoming by South American water snakes Helicops angulatus and Hydrops triangularis from Bolivian Amazon: A one-year prospective study of non-front-fanged colubroid snakebites.

Although snakebite incidence is underestimated in Bolivia, the Amazon region presents the highest incidence of these accidents. The local effects of bites by some non-front-fanged colubroid (NFFC) snakes are usually confused with that of viperids, resulting in the improper use of antivenoms and medications. Since there is scarce information on clinical treatment and management of NFFC bites from Bolivian Amazon, we conducted a prospective study of NFFC snakebites by reviewing the records of patients admitted with a snakebite diagnosis at Hospital Central Ivirgarzama, Bolivia. Snakebites were recorded for 12 months (December 2019-November 2020), including information about the sex and age of the patient, snakebite date, and treatment. Eight (5.7 %) of 152 patients were bitten by NFFC Helicops angulatus, Hydrops triangularis, and Erythrolamprus sp. Our results showed that 5/7 patients had prolonged clotting time and INR, as well as local edema and mild pain, suggesting systemic envenoming. Previously non-documented mild coagulopathy was observed for H. angulatus and H. triangularis bites. In some cases, incorrect first-aid measures, and inappropriate use of bothropic/lachesic antivenom were administrated. All the patients received supportive therapy and antihistamine drugs. Unsupported use of non-evidence-based treatments for snakebites such as corticoids, non-steroidal anti-inflammatory drugs (NSAIDs), and prophylactic antibiotic prescription were recorded. In conclusion, we describe the first formally documented snakebite cases produced by NFFC from Bolivia, highlighting the urgent need for training of the medical team in the snake identification, clinical management of snakebite, and the existence of a human-snake conflict involving NFFC species.

Single-Arm, Multicenter Phase I/II Clinical Trial for the Treatment of Envenomings by Massive Africanized Honey Bee Stings Using the Unique Apilic Antivenom.

We evaluated the safety, optimal dose, and preliminary effectiveness of a new-approach Africanized honeybee (Apis mellifera) Antivenom (AAV) in a phase I/II, multicenter, non-randomized, single-arm clinical trial involving 20 participants with multiple stings. Participants received 2 to 10 vials of AAV depending on the number of stings they suffered, or a predefined adjuvant, symptomatic, and complementary treatment. The primary safety endpoint was the occurrence of early adverse reactions within the first 24 h of treatment. Preliminary efficacy based on clinical evolution, including laboratory findings, was assessed at baseline and at various time points over the four following weeks. ELISA assays and mass spectrometry were used to estimate venom pharmacokinetics before, during, and after treatment. Twenty adult participants, i.e., 13 (65%) men and 7 (35%) women, with a median age of 44 years and a mean body surface area of 1.92 m2 (median = 1.93 m2) were recruited. The number of stings ranged from 7 to > 2,000, with a median of 52.5. Symptoms of envenoming were classified as mild, moderate, or severe in 80% (16), 15% (3), and 5% (1) of patients, respectively; patients with mild, moderate, or severe envenoming received 2, 6, and 10 vials of AAV as per the protocol. None of the patients had late reactions (serum sickness) within 30 d of treatment. There was no discontinuation of the protocol due to adverse events, and there were no serious adverse events. One patient had a moderate adverse event, transient itchy skin, and erythroderma. All participants completed the intravenous antivenom infusion within 2 h, and there was no loss to follow-up after discharge. ELISA assays showed venom (melittin and PLA2) concentrations varying between 0.25 and 1.479 ng/mL prior to treatment. Venom levels decreased in all patients during the hospitalization period. Surprisingly, in nine cases (45%), despite clinical recovery and the absence of symptoms, venom levels increased again during outpatient care 10 d after discharge. Mass spectrometry showed melittin in eight participants, 30 d after treatment. Considering the promising safety results for this investigational product in the treatment of massive Africanized honeybee attack, and its efficacy, reflected in the clinical improvements and corresponding immediate decrease in blood venom levels, the AAV has shown to be safe for human use. Clinical Trial Registration: UTN: U1111-1160-7011, identifier [RBR-3fthf8].

Report of a severe Heloderma suspectum envenomation.

BACKGROUND: Heloderma bites are rare and generally mild, but a few cases can be life threatening. CASE REPORT: We report a case of Heloderma suspectum envenomation in a healthy 39-year-old herpetologist. The patient rapidly developed tongue and lip swelling associated with stridor. On arrival at ICU, he was hypotensive, and in shock with atrial fibrillation requiring electrical cardioversion. Blood tests showed hypokalemia (2 mmol·L-1), associated with moderate low blood electrolytes which were corrected rapidly. In addition, he presented hematological abnormalities (INR = 1.34 and fibrinogen levels at 80 mg·dL-1) without active bleeding. All clinical and biological signs normalized without specific intervention and was discharged 4 days post-bite. The patient discharged 3 days after hospital presentation and fully recovered in 2 months. DISCUSSION/CONCLUSION: The case presented here showed the three severe complications described after Heloderma bite: a) angioedema, b) fluid loss associated with hypokalemia and metabolic acidosis, and c) cardiac disorders simulating ischemia.

Single-arm, multicenter phase I/II clinical trial for the treatment of envenomings by massive africanized honey bee stings using the unique apilic antivenom

We evaluated the safety, optimal dose, and preliminary effectiveness of a new-approach Africanized honeybee (Apis mellifera) Antivenom (AAV) in a phase I/II, multicenter, non-randomized, single-arm clinical trial involving 20 participants with multiple stings. Participants received 2 to 10 vials of AAV depending on the number of stings they suffered, or a predefined adjuvant, symptomatic, and complementary treatment. The primary safety endpoint was the occurrence of early adverse reactions within the first 24 h of treatment. Preliminary efficacy based on clinical evolution, including laboratory findings, was assessed at baseline and at various time points over the four following weeks. ELISA assays and mass spectrometry were used to estimate venom pharmacokinetics before, during, and after treatment. Twenty adult participants, i.e., 13 (65%) men and 7 (35%) women, with a median age of 44 years and a mean body surface area of 1.92 m2 (median = 1.93 m2) were recruited. The number of stings ranged from 7 to > 2,000, with a median of 52.5. Symptoms of envenoming were classified as mild, moderate, or severe in 80% (16), 15% (3), and 5% (1) of patients, respectively; patients with mild, moderate, or severe envenoming received 2, 6, and 10 vials of AAV as per the protocol. None of the patients had late reactions (serum sickness) within 30 d of treatment. There was no discontinuation of the protocol due to adverse events, and there were no serious adverse events. One patient had a moderate adverse event, transient itchy skin, and erythroderma. All participants completed the intravenous antivenom infusion within 2 h, and there was no loss to follow-up after discharge. ELISA assays showed venom (melittin and PLA2) concentrations varying between 0.25 and 1.479 ng/mL prior to treatment. Venom levels decreased in all patients during the hospitalization period. Surprisingly, in nine cases (45%), despite clinical recovery and the absence of symptoms, venom levels increased again during outpatient care 10 d after discharge. Mass spectrometry showed melittin in eight participants, 30 d after treatment. Considering the promising safety results for this investigational product in the treatment of massive Africanized honeybee attack, and its efficacy, reflected in the clinical improvements and corresponding immediate decrease in blood venom levels, the AAV has shown to be safe for human use. Clinical Trial Registration: UTN: U1111-1160-7011, identifier [RBR-3fthf8].

Acute kidney failure following severe viper envenomation: clinical, biological and ultrasonographic aspects.

BACKGROUND: Acute kidney injury (AKI) is a frequent complication of snakebite envenomation, which is still little known in sub-Saharan Africa. This study aims to describe the clinical, biological and ultrasonographic aspects of AKI following severe snakebite envenomation managed in the intensive care unit. METHOD: A prospective observational survey was performed in Benin over a period of 18 months. All patients suffering severe snakebite envenomation (SBE) were included. The diagnosis of AKI was made using the KDIGO criteria. Kidney ultrasound exam was performed in all patients to assess internal bleeding and morphological and structural abnormalities of the kidneys. RESULTS: Fifty-one cases of severe SBE were included. All patients presented inflammatory syndrome and showed abnormal WBCT whereas bleeding was found in 46 of them (90%). The median time to hospital presentation was three days. The majority of patients were male (M/F sex ratio = 1.55) and the median age was 26. Sixteen patients (31%) showed AKI according to the KDIGO criteria. Severe AKI (KDIGO stage 2 and 3) was observed in three patients, including one stage 2 and two stage 3. Kidney ultrasound revealed three cases of kidney capsular hematoma (6%), two cases of kidney hypertrophy (3%), three cases of kidney injury (4%), two stage 1 KDIGO and one stage 2 KDIGO. Only one patient benefited from hemodialysis. All patients showing AKI recovered without sequels. The median duration of hospital stays was four days. Seven patients died (14%) including four among the 16 AKI patients. Antivenom has been administered to 41 patients (80%). The comparison between patients without and with AKI did not show any significant difference except gender (p = 10-2). CONCLUSION: AKI is a common complication of severe snakebite envenomation. Resulting from inflammatory and hemorrhagic disorders, AKI may prove to be a short-term life-threatening factor.

Acute kidney failure following severe viper envenomation: clinical, biological and ultrasonographic aspects

Acute kidney injury (AKI) is a frequent complication of snakebite envenomation, which is still little known in sub-Saharan Africa. This study aims to describe the clinical, biological and ultrasonographic aspects of AKI following severe snakebite envenomation managed in the intensive care unit. Method: A prospective observational survey was performed in Benin over a period of 18 months. All patients suffering severe snakebite envenomation (SBE) were included. The diagnosis of AKI was made using the KDIGO criteria. Kidney ultrasound exam was performed in all patients to assess internal bleeding and morphological and structural abnormalities of the kidneys. Results: Fifty-one cases of severe SBE were included. All patients presented inflammatory syndrome and showed abnormal WBCT whereas bleeding was found in 46 of them (90%). The median time to hospital presentation was three days. The majority of patients were male (M/F sex ratio = 1.55) and the median age was 26. Sixteen patients (31%) showed AKI according to the KDIGO criteria. Severe AKI (KDIGO stage 2 and 3) was observed in three patients, including one stage 2 and two stage 3. Kidney ultrasound revealed three cases of kidney capsular hematoma (6%), two cases of kidney hypertrophy (3%), three cases of kidney injury (4%), two stage 1 KDIGO and one stage 2 KDIGO. Only one patient benefited from hemodialysis. All patients showing AKI recovered without sequels. The median duration of hospital stays was four days. Seven patients died (14%) including four among the 16 AKI patients. Antivenom has been administered to 41 patients (80%). The comparison between patients without and with AKI did not show any significant difference except gender (p = 10-2). Conclusion: AKI is a common complication of severe snakebite envenomation. Resulting from inflammatory and hemorrhagic disorders, AKI may prove to be a short-term life-threatening factor.(AU)

Acute kidney failure following severe viper envenomation: clinical, biological and ultrasonographic aspects

Acute kidney injury (AKI) is a frequent complication of snakebite envenomation, which is still little known in sub-Saharan Africa. This study aims to describe the clinical, biological and ultrasonographic aspects of AKI following severe snakebite envenomation managed in the intensive care unit. Method: A prospective observational survey was performed in Benin over a period of 18 months. All patients suffering severe snakebite envenomation (SBE) were included. The diagnosis of AKI was made using the KDIGO criteria. Kidney ultrasound exam was performed in all patients to assess internal bleeding and morphological and structural abnormalities of the kidneys. Results: Fifty-one cases of severe SBE were included. All patients presented inflammatory syndrome and showed abnormal WBCT whereas bleeding was found in 46 of them (90%). The median time to hospital presentation was three days. The majority of patients were male (M/F sex ratio = 1.55) and the median age was 26. Sixteen patients (31%) showed AKI according to the KDIGO criteria. Severe AKI (KDIGO stage 2 and 3) was observed in three patients, including one stage 2 and two stage 3. Kidney ultrasound revealed three cases of kidney capsular hematoma (6%), two cases of kidney hypertrophy (3%), three cases of kidney injury (4%), two stage 1 KDIGO and one stage 2 KDIGO. Only one patient benefited from hemodialysis. All patients showing AKI recovered without sequels. The median duration of hospital stays was four days. Seven patients died (14%) including four among the 16 AKI patients. Antivenom has been administered to 41 patients (80%). The comparison between patients without and with AKI did not show any significant difference except gender (p = 10-2). Conclusion: AKI is a common complication of severe snakebite envenomation. Resulting from inflammatory and hemorrhagic disorders, AKI may prove to be a short-term life-threatening factor.(AU)

The WHO strategy for prevention and control of snakebite envenoming: a sub-Saharan Africa plan.

Snakebite is a critical public health issue in tropical countries, particularly in Africa, where 20% of snakebites globally occur. In 2017, the WHO added snakebite envenoming to the category A of neglected tropical diseases. In 2019, thanks to broad institutional and international NGO support, including strong mobilization of African experts and governments, WHO launched a strategy for prevention and control of snakebite envenoming with more ambitious goals. In sub-Saharan Africa, accessibility of antivenoms and symptomatic, adjuvant or replacement therapy is a priority. Several antivenoms are available but their evaluation has not been properly carried out and they remain expensive. To date, there are no manufacturers of antivenom in sub-Saharan Africa (except in South Africa), which requires their importation from other continents. The lack of experience in antivenom choice and its use by health authorities, health personnel and population largely explains the shortage in sub-Saharan Africa. The deficiency of epidemiological data does not allow the implementation of appropriate and efficient care. It is crucial to strengthen the health system which does not have the necessary means for emergency management in general and envenoming in particular. Providing peripheral health centers with antivenoms would decrease complications and deaths. The motivation of communities at risk, identified through the epidemiological data, would be to reduce the delay in consultation that is detrimental to the efficiency of treatment. Partnerships need to be coordinated to optimize resources from international institutions, particularly African ones, and share the burden of treatment costs among all stakeholders. We propose here a project of progressive implementation of antivenom manufacturing in sub-Saharan Africa. The various steps, from the supply of appropriate venoms to the production of purified specific antibodies and vial filling, would be financed by international, regional and local funding promoting technology transfer from current manufacturers compensated by interest on the sale of antivenoms.

The WHO strategy for prevention and control of snakebite envenoming: a sub-Saharan Africa plan

Snakebite is a critical public health issue in tropical countries, particularly in Africa, where 20% of snakebites globally occur. In 2017, the WHO added snakebite envenoming to the category A of neglected tropical diseases. In 2019, thanks to broad institutional and international NGO support, including strong mobilization of African experts and governments, WHO launched a strategy for prevention and control of snakebite envenoming with more ambitious goals. In sub-Saharan Africa, accessibility of antivenoms and symptomatic, adjuvant or replacement therapy is a priority. Several antivenoms are available but their evaluation has not been properly carried out and they remain expensive. To date, there are no manufacturers of antivenom in sub-Saharan Africa (except in South Africa), which requires their importation from other continents. The lack of experience in antivenom choice and its use by health authorities, health personnel and population largely explains the shortage in sub-Saharan Africa. The deficiency of epidemiological data does not allow the implementation of appropriate and efficient care. It is crucial to strengthen the health system which does not have the necessary means for emergency management in general and envenoming in particular. Providing peripheral health centers with antivenoms would decrease complications and deaths. The motivation of communities at risk, identified through the epidemiological data, would be to reduce the delay in consultation that is detrimental to the efficiency of treatment. Partnerships need to be coordinated to optimize resources from international institutions, particularly African ones, and share the burden of treatment costs among all stakeholders. We propose here a project of progressive implementation of antivenom manufacturing in sub-Saharan Africa. The various steps, from the supply of...(AU)

Ethnomedicinal plants used for snakebite treatments in Ethiopia: a comprehensive overview.

Traditional medicine plays an important role in the daily lives of people living in rural parts of Ethiopia. Despite the fact that Ethiopia has a long history of using traditional medicinal plants as an alternative medicine source, there is no checklist compiling these plants used for snakebite treatment. This review collected and compiled available knowledge on and practical usage of such plants in the country. A literature review on medicinal plants used to treat snakebites was conducted from 67 journal articles, PhD dissertation and MSc theses available online. Data that summarize scientific and folk names, administration methods, plant portion used for treatment and method of preparation of recipes were organized and analyzed based on citation frequency. The summarized results revealed the presence of 184 plant species distributed among 67 families that were cited for treating snakebite in Ethiopia. In this literature search, no single study was entirely dedicated to the study of traditional medicinal plants used for the treatment of snakebite in Ethiopia. Most of the species listed as a snakebite remedy were shrubs and climbers (44%) followed by herbs (33%) and trees (23%). Fabaceae was the most predominant family with the greatest number of species, followed by Solanaceae and Vitaceae. Remedies are mainly prepared from roots and leaves, through decoctions, infusions, powders and juices. Most remedies were administered orally (69%). The six most frequently mentioned therapeutically important plants were Nicotiana tabacum, Solanum incanum, Carissa spinanrum, Calpurnia aurea, Croton macrostachyus and Cynodon dactylon. Authors reviewed the vegetal substances involved in snakebite management and their action mode. In addition to screening the biologically active ingredients and pharmacological activities of these plant materials, future studies are needed to emphasize the conservation and cultivation of important medicinal plants of the country.

Ethnomedicinal plants used for snakebite treatments in Ethiopia: a comprehensive overview

Traditional medicine plays an important role in the daily lives of people living in rural parts of Ethiopia. Despite the fact that Ethiopia has a long history of using traditional medicinal plants as an alternative medicine source, there is no checklist compiling these plants used for snakebite treatment. This review collected and compiled available knowledge on and practical usage of such plants in the country. A literature review on medicinal plants used to treat snakebites was conducted from 67 journal articles, PhD dissertation and MSc theses available online. Data that summarize scientific and folk names, administration methods, plant portion used for treatment and method of preparation of recipes were organized and analyzed based on citation frequency. The summarized results revealed the presence of 184 plant species distributed among 67 families that were cited for treating snakebite in Ethiopia. In this literature search, no single study was entirely dedicated to the study of traditional medicinal plants used for the treatment of snakebite in Ethiopia. Most of the species listed as a snakebite remedy were shrubs and climbers (44%) followed by herbs (33%) and trees (23%). Fabaceae was the most predominant family with the greatest number of species, followed by Solanaceae and Vitaceae. Remedies are mainly prepared from roots and leaves, through decoctions, infusions, powders and juices. Most remedies were administered orally (69%). The six most frequently mentioned therapeutically important plants were Nicotiana tabacum, Solanum incanum, Carissa spinanrum, Calpurnia aurea, Croton macrostachyus and Cynodon dactylon. Authors reviewed the vegetal substances involved in snakebite management and their action mode. In addition to screening the biologically active ingredients and pharmacological activities of these plant materials, future studies are needed to emphasize the conservation and cultivation of important medicinal plants of the country.(AU)

The WHO strategy for prevention and control of snakebite envenoming: a sub-Saharan Africa plan

Snakebite is a critical public health issue in tropical countries, particularly in Africa, where 20% of snakebites globally occur. In 2017, the WHO added snakebite envenoming to the category A of neglected tropical diseases. In 2019, thanks to broad institutional and international NGO support, including strong mobilization of African experts and governments, WHO launched a strategy for prevention and control of snakebite envenoming with more ambitious goals. In sub-Saharan Africa, accessibility of antivenoms and symptomatic, adjuvant or replacement therapy is a priority. Several antivenoms are available but their evaluation has not been properly carried out and they remain expensive. To date, there are no manufacturers of antivenom in sub-Saharan Africa (except in South Africa), which requires their importation from other continents. The lack of experience in antivenom choice and its use by health authorities, health personnel and population largely explains the shortage in sub-Saharan Africa. The deficiency of epidemiological data does not allow the implementation of appropriate and efficient care. It is crucial to strengthen the health system which does not have the necessary means for emergency management in general and envenoming in particular. Providing peripheral health centers with antivenoms would decrease complications and deaths. The motivation of communities at risk, identified through the epidemiological data, would be to reduce the delay in consultation that is detrimental to the efficiency of treatment. Partnerships need to be coordinated to optimize resources from international institutions, particularly African ones, and share the burden of treatment costs among all stakeholders. We propose here a project of progressive implementation of antivenom manufacturing in sub-Saharan Africa. The various steps, from the supply of...

Ethnomedicinal plants used for snakebite treatments in Ethiopia: a comprehensive overview

Traditional medicine plays an important role in the daily lives of people living in rural parts of Ethiopia. Despite the fact that Ethiopia has a long history of using traditional medicinal plants as an alternative medicine source, there is no checklist compiling these plants used for snakebite treatment. This review collected and compiled available knowledge on and practical usage of such plants in the country. A literature review on medicinal plants used to treat snakebites was conducted from 67 journal articles, PhD dissertation and MSc theses available online. Data that summarize scientific and folk names, administration methods, plant portion used for treatment and method of preparation of recipes were organized and analyzed based on citation frequency. The summarized results revealed the presence of 184 plant species distributed among 67 families that were cited for treating snakebite in Ethiopia. In this literature search, no single study was entirely dedicated to the study of traditional medicinal plants used for the treatment of snakebite in Ethiopia. Most of the species listed as a snakebite remedy were shrubs and climbers (44%) followed by herbs (33%) and trees (23%). Fabaceae was the most predominant family with the greatest number of species, followed by Solanaceae and Vitaceae. Remedies are mainly prepared from roots and leaves, through decoctions, infusions, powders and juices. Most remedies were administered orally (69%). The six most frequently mentioned therapeutically important plants were Nicotiana tabacum, Solanum incanum, Carissa spinanrum, Calpurnia aurea, Croton macrostachyus and Cynodon dactylon. Authors reviewed the vegetal substances involved in snakebite management and their action mode. In addition to screening the biologically active ingredients and pharmacological activities of these plant materials, future studies are needed to emphasize the conservation and cultivation of important medicinal plants of the country.(AU)

Yellow fever in Africa and the Americas: a historical and epidemiological perspective.

Yellow fever was transported during the slave trade in the 15th and 16th centuries from Africa to the Americas where the virus encountered favorable ecological conditions that allowed creation of a sustainable sylvatic cycle. Despite effective vector control and immunization programs for nearly a century, yellow fever epidemics reemerged in many Latin American countries, particularly Brazil. The emergence or reemergence of vector-borne diseases encompasses many intricate factors. Yellow fever outbreaks occur if at least three conditions are fulfilled: the introduction of the virus into a non-immune human community, presence of competent and anthropophilic vectors and insufficiency of prevention and/or adequate management of the growing outbreak. On the other hand, two weapons are available to constrain yellow fever: vector control and immunization. In contrast, yellow fever is absent from Asia and the Pacific despite the presence of the vector and the susceptibility of human populations to the virus. Based on a review of the global history of yellow fever and its epidemiology, the authors deliver some recommendations for improving the prevention of epidemics.

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

BACKGROUND: 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). WBCT discrepancies were encountered most frequently in three situations: initial normalization of hemostasis following antivenom therapy, detection of a secondary resumption of coagulopathy, or final restoration of hemostasis after a secondary resumption had occurred. CONCLUSIONS: This study suggests that the WBCT is robust and that a sequential reading should improve the diagnosis and monitoring of venom-induced coagulopathies. It also indicates the possibility of discrepancies in the sensitivity of WBCT20 and WBCT30 for detecting the resolution or reoccurrence of coagulopathy and identifies how these findings, if confirmed, may be used to increase the efficacy and efficiency of antivenom treatment in the field.

Yellow fever in Africa and the Americas: a historical and epidemiological perspective

Yellow fever was transported during the slave trade in the 15th and 16th centuries from Africa to the Americas where the virus encountered favorable ecological conditions that allowed creation of a sustainable sylvatic cycle. Despite effective vector control and immunization programs for nearly a century, yellow fever epidemics reemerged in many Latin American countries, particularly Brazil. The emergence or reemergence of vector-borne diseases encompasses many intricate factors. Yellow fever outbreaks occur if at least three conditions are fulfilled: the introduction of the virus into a non-immune human community, presence of competent and anthropophilic vectors and insufficiency of prevention and/or adequate management of the growing outbreak. On the other hand, two weapons are available to constrain yellow fever: vector control and immunization. In contrast, yellow fever is absent from Asia and the Pacific despite the presence of the vector and the susceptibility of human populations to the virus. Based on a review of the global history of yellow fever and its epidemiology, the authors deliver some recommendations for improving the prevention of epidemics.(AU)