Epidemic of self-poisoning with seeds of the yellow oleander tree (Thevetia peruviana) in northern Sri Lanka

Deliberate self-harm is an important problem in the developing world. Ingestion of yellow oleander seeds (Thevetia peruviana) has recently become a popular method of self-harm in northern Sri Lanka -- there are now thousands of cases each year. These seeds contain cardiac glycosides that cause vomiting, dizziness, and cardiac dysrhythmias such as conduction block affecting the sinus and AV nodes. This paper reports a study of the condition's mortality and morbidity conducted in 1995 in Anuradhapura General Hospital, a secondary referral centre serving 750 000 people in Sri Lanka's north central province. 415 cases were admitted to the hospital during 11 months; 61% were women and 46% were less than 21 years old. A prospective study of 79 patients showed that 6% died soon after admission. 43% presented with marked cardiac dysrhythmias which necessitated ther transfer to the coronary care unit in Colombo for prophylactic temporary cardiac pacing. The reasons for the acts of self-harm were often relatively trivial, particularly in children; most denied that they wished to die. Unfortunately, the case fatality rate for oleander poisoning in Sri Lanka is at least 10%. This epidemic is not only causing many unnecessary deaths, it is also putting immense stress on the already stretched Sri Lankan health services. There is an urgent need for an intervention which could be used in rural hospitals, thus preventing the hazardous and expensive emergency transfer of patients to the capital.

Variable major lipoprotein is a principal TNF-inducing factor of louse-borne relapsing fever

Massive release of tumor necrosis factor is responsible for the potentially fatal larisch-Herxheimer reaction that follows antibiotic treatment of relapsing fever due to Borrelia recurrentis. We have undertaken the quantitative purification of the components of B. recurrentis that stimulate human monocytes to produce tumor necrosis factor. We show that the predominant factor inducing tumor necrosis factor is a variable lipoprotein homologous to the variable major protein of B. hermsii. We found antibodies to different forms of variable major protein in two patients with louse-borne relapsing fever. The three purified variable major proteins studied here differ in their ability to induce tumor necrosis factor production, which may partly explain the variable clinical severity of borrelial infection. These results may be of considerable relevance for the pathogenesis of Lyme disease and other forms of human borreliosis.

Some effects of the rising case load of adult HIV-related disease on a hospital in Nairobi

Increasing numbers of HIV-infected adults in Africa need hospital care. It remains unclear what impact this has on health care services or on how hospitals respond. The aim of this study was to describe the effects of a rising case load of adult HIV-related disease by comparing results from a prospective cross-sectional study of acute adult medical admissions to a government hospital in Nairobi conducted in 1992 with results from a previous study done in 1988 and 1989 in the same hospital, using the same study design and protocol. Data on age, gender, number admitted, length of stay, HIV status, clinical AIDS, final diagnosis, case mix, and outcome were compared. In 1992, 374 consecutive patients were admitted in 15 24-hour periods (24.9 patients/period) compared with the 1988 to 1989 study, which enrolled 506 patients in 22 24-hour periods (23.0 patients/period). Patients' age, gender, and length of hospital stay were similar in both studies. In 1992, 39% of patients were HIV-positive compared with 19% in 1988 to 1989 (p < 10(-6)); whereas seropositive admissions rose 123% between the two periods (p < .0001), HIV-negative admissions declined 18% (p < .05). Clinical surveillance for AIDS consistently identified <40% of HIV-positive patients. Irrespective of HIV status, tuberculosis and pneumococcal pneumonia were the leading diagnoses in both surveys. No change was found in the diagnoses recorded for HIV-positive patients, but in HIV-negative patients, reductions were significant in the case mix (p < .00001) and range of diagnoses (p < .001) seen in 1992. Outcome remained unchanged for HIV-positive patients with approximately 35% mortality in both surveys. Outcome significantly worsened, in relative and absolute terms, for HIV-negative patients: in 1992, mortality was 23%, compared with 13.9% in 1988 to 1989 (p < .005), with 3.5 deaths per 24-hour period in 1992 compared with 2.6 deaths per 24-hour period in 1988 to 1989 (p < .05, one-tailed). These data suggest that increasing selection for admission is taking place as demand for care increases because of HIV/AIDS. This process appears to favor HIV-positive patients at the expense of HIV-negative patients who seem to be crowded out and, once admitted, experience higher mortality rates. The true social costs of the HIV epidemic are underestimated by not including the effects on HIV-negative people.

Neurological manifestations of falciparum malaria

Plasmodium falciparum remains one of the most common causes of central nervous system infection worldwide. Recently, differences between the pathophysiology of cerebral malaria in African children and nonimmune adults have been discovered, new syndromes occurring after malaria infection described, and mechanisms for the pathogenesis proposed. In addition, new antimalarial agents have been examined worldwide and initial studies on supportive studies conducted. This paper reviews these new advances, putting them into the perspective of the more established knowledge.

Randomized comparison of intramuscular artemether and intravenous quinine in adult, Melanesian patients with severe or complicated, Plasmodium falciparum malaria in Papua New Guinea

An open-label, randomized, controlled trial was used to compare the safety and efficacy of intramuscular artemether (a loading dose of 3.2 mg/kg, followed by 1.6 mg/kg daily for 4 days) and intravenous quinine (a loading dose of 20 mg quinine dihydrochloride/kg, followed first by 10 mg/kg every 8 h, each injection taking 4 h, for at least 48 h, and then oral quinine for a total of 7 days) in the management of strictly defined severe/complicated malaria in Melanesian adults. Four (12%) of the 33 patients who enrolled and completed follow-up died (one of the 15 who received artemether and three of the 18 who received quinine). Overall, cerebral malaria was uncommon (6%) whilst jaundice was common (76%). The time taken to clear 50% of parasites was less in those treated with artemether (median = 8 h; range = 2-24 h) than in the patients given quinine (median = 14 h; range = 2-25 h; P = 0.05). Temperature defervescence was also quicker in those treated with artemether (median = 32 hours; range = 20-112 h) than in those in the quinine group (median = 48 h; range = 28-88 h; P = 0.034). Hypoglycaemia was not observed in any patient treated with artemether but complicated therapy in 11 (79%) of the 14 patients given quinine who had not had pre-treatment spontaneous hypoglycaemia. No serious adverse effects were attributable to artemether. The Plasmodium falciparum infections observed during the 1 month of follow-up, in three patients who had received artemether and two who had been given quinine, were probably due to recrudescence. Plasmodium vivax parasitaemias were also observed during follow-up, in one or two patients in each treatment group. Artemether appears safe in Melanesian adults and is probably as effective as intravenous quinine in the treatment of severe or complicated falciparum malaria.

Synopsis of recent developments in venomous snake systematics, No. 2

Developments in our understanding of the systematics of venomous snakes since the beginning of 1996 are discussed and reviewed with special emphasis on their relevance and implications for toxinologists and clinicians. Groups of snakes affected by recent developments include the genera Elapomorphus, Rhabdophis, Vermicella, Atheris, Daboia, Agkistrodon/Gloydius, Bothrops/Bothriopsis and Trimeresurus. Other important publications on venomous snakes are noted.

High incidence of early anaphylactoid reaction to SAIMR polyvalent snake antivenom

During a prospective study of 147 patients with snakebite presenting to a rural South African hospital, 13 of 17 patients (76%) treated with South African Institute for Medical Research (SAIMR) polyvalent antivenom experienced potentially severe early (anaphylactoid) reactions. The most common reaction was generalized urticaria (12; 71%), but 3 cases of angio-oedema (18%), 2 of bronchospasm (12%), and 2 of hypotension (12%) were also observed. Reactions were controlled with adrenaline, antihistamines, and resuscitation. All patients fully recovered from envenoming although the full dose of antivenom was not given to most. Indications for the use of this antivenom should be reconsidered and patients should be given antivenom in a high care setting if possible. Use of antivenom by lay people outside hospital should be discouraged and antivenom manufacturing processes could usefully be reviewed.

Cerebral malaria: clinical features, pathophysiology and treatment

Herbert Gilles played an important role in the establishment of the Wellcome-Mahidol University, Oxford Tropical Medicine Research Programme in Thailand in 1979. The randomized, placebo-controlled trial of dexamethasone in cerebral malaria that was carried out in Chantaburi in 1980 yielded results which led to the abandonment of ancillary corticosteroid therapy in this disease and contributed to a rejection of the 'permeability hypothesis'. The clinical manifestations of strictly defined cerebral malaria have not been described both in non-immune adults in Thailand and Vietnam and in African children. Clinical and histopathological studies in human patients, together with laboratory studies of cyto-adherence, malaria 'toxin' and cytokine production have provided some evidence for both the 'mechanical' and 'toxin-cytokine' hypotheses to explain the pathophysiology of this condition. Chemotherapy is challenged by the continuing evolution of antimalarial resistance. Recently, the most powerful studies ever carried out with antimalarial drugs have demonstrated that artemether and quinine achieve similar case fatalities, in the range 11%-21%, and that both drugs have some advantages and disadvantages. Further studies are needed to define the efficacy and safety of prophylactic anticonvulsants and exchange transfusion in cerebral malaria. Cerebral malaria remains a major cause of mortality and, in African children, morbidity.

Recent transmission of tuberculosis in a cohort of HIV-1-infected female sex workers in Nairobi, Kenya

OBJECTIVES

To describe the epidemiological and clinical characteristics of HIV-related tuberculosis in a female cohort, and to investigate the relative importance of recently transmitted infection and reactivation in the pathogenesis of adult HIV-related tuberculosis.

DESIGN

Members of an established cohort of female sex workers in Nairobi were enrolled in a prospective study. Women were followed up regularly and seen on demand when sick.

METHODS

Between October 1989 and September 1992 we followed 587 HIV-infected and 132 HIV-seronegative women. Standard protocols were used to investigate common presentations. Cases of tuberculosis were identified clinically or by culture. All available Mycobacterium tuberculosis strains underwent DNA fingerprint analysis.

RESULTS

Forty-nine incident and four recurrent episodes of tuberculosis were seen in HIV-infected women; no disease was seen in seronegative sex workers (P = 0.0003). The overall incidence rate of tuberculosis was 34.5 per 1000 person-years amongst HIV-infected participants. In purified protein derivative (PPD) skin test-positive women the rate was 66.7 per 1000 person-years versus 18.1 per 1000 person-years in PPD-negative women. Twenty incident cases (41%) were clinically compatible with primary disease. DNA fingerprint analysis of strains from 32 incident cases identified two clusters comprising two and nine patients; allowing for index cases, 10 patients (28%) may have had recently transmitted disease. Three out of 10 (30%) patients who were initially PPD skin test-negative became PPD-positive. Taken together, 26 incident cases (53%) may have been recently infected. DNA fingerprint analysis also identified two (50%) of the four recurrent tuberculosis episodes as reinfection.

CONCLUSIONS

Substantial recent transmission of tuberculosis appears to be occurring in Nairobi amongst HIV-infected sex workers. It may be incorrect to assume in other regions of high tuberculosis transmission that active HIV-related tuberculosis usually represents reactivation of latent infection.

Snake bites by the jararacuçu (Bothrops jararacussu): clinicopathological studies of 29 proven cases in São Paulo State, Brazil

The jararacuçu, one of the most dreaded snakes of Brazil, southern Bolivia, Paraguay and northeastern Argentina, is a heavily-built pit viper which may grow to a length of 2.2 m. Up to 1000 mg (dry weight) of highly-lethal venom may be milked from its venom glands on a single occasion. It has accounted for 0.8% to 10% of series of snake bites in São Paulo State, Brazil. We examined 29 cases of proven jararacuçu bites recruited over a 20-year period in two São Paulo hospitals. Severe signs of local and systemic envenoming, (local necrosis, shock, spontaneous systemic bleeding, renal failure) were seen only in patients bitten by snakes longer than 50 cm; bites by shorter specimens were more likely to cause incoagulable blood. Fourteen patients developed coagulopathy, six local necrosis (requiring amputation in one) and five local abscesses. Two became shocked and four developed renal failure. Three patients, aged 3, 11 and 65 years, died 18.75, 27.75 and 83 h after being bitten, with respiratory and circulatory failure despite large doses of specific antivenom and intensive-care-unit management. In two patients, autopsies revealed acute renal tubular necrosis, cerebral oedema, haemorrhagic rhabdomyolysis at the site of the bite and disseminated intravascular coagulation. In one survivor with chronic renal failure, renal biopsy showed bilateral cortical necrosis; the patient remains dependent on haemodialysis. Effects of polyspecific Bothrops antivenom were not impressive, and it has been suggested that anti-Bothrops and anti-Crotalus antivenoms should be given in combination.

The 1996 Runme Shaw Memorial Lecture: malaria--past, present and future

Falciparum malaria may have infected Homo sapiens (and perhaps H erectus) in the Asia Pacific region for more than 100,000 years. This estimate is based on the gene frequency of alpha-thalassaemia, the protection it affords against falciparum malaria and assumptions of untreated mortality from the infection. Up until the end of the 19th century, there was a high mortality from malaria in the coastal parts of Malaya, but the malaria control campaign, begun in 1901 at Klang, was described by Sir Ronald Ross as the first successful antimalarial work in the (then) British Empire. This was extended to Singapore in 1911. When the Far Eastern Association of Tropical Medicine held its Fifth Biennial Congress in Singapore in 1923, malaria was still a major killing disease in parts of Malaya and Sarawak. The mechanism of life-threatening malaria involves cytoadherence of parasitised erythrocytes in microvascular beds, a process enhanced by the products of macrophage activation induced by malarial pyrogen. Improvements in the chemotherapy of life-threatening falciparum malaria with chloroquine and quinine have been countered by the emergence of resistant strains. Artemisinin derivatives may become the treatment of choice during the coming decade. Apart from traditional anti-mosquito methods, control of malaria now involves the use of insecticide-impregnated bed nets, new entomological strategies, including genetic manipulation of mosquitoes and selective chemoprophylaxis. Antigenic diversity and antigenic variation of the malaria parasite have so far defeated attempts to produce an effective vaccine.

Sensitivity to bee and wasp venoms: association with specific IgE responses to the bee and wasp venom and HLA DRB1 and DPB1

BACKGROUND

Stings from bees and wasps can cause systemic reactions which can be fatal in some individuals. In these venom-sensitive patients, specific IgE to the venom is produced and is considered to participate in the adverse reactions. This immune response requires antigen presentation by human leucocyte antigens (HLA) class II molecules, which includes DR and DP, which are present on antigen presenting cells.

OBJECTIVE

To test for associations between HLA class II DRB1 and DPB1 alleles and life-threatening sensitivity to both bee and wasp venoms. To establish further whether any associations are independent of the atopy phenotype.

METHODS

A total of 33 bee- and 44 wasp-venom-sensitive patients was studied. DRB1 genotypes were determined by single stranded oligonucleotide (SSO) probing of PCR products, and DPB1 genotypes by amplified fragment length polymorphism (AFLP) analysis. Total and specific IgE were measured using the Pharmacia Immunocap, FEIA. Patients with specific IgE to the venom antigens only were termed monosensitive and those with additional specific IgE to HDM and/or GP were termed polysensitive.

RESULTS

Allele frequencies were compared to an unrelated control population. The 33 bee-sensitive patients had a greater prevalence of DRB1*07 alleles than the control subjects, 26% vs 14%, with an odds ratio (OR) of 2.1 (95% CI, 1.2-3.7, P = 0.015, corrected for multiple comparisons, Pc = ns). This association was confined to the 15 monosensitive bee patients, who had a 43% DRB1*07 allele frequency when compared with 11% in the 18 polysensitive bee patients, OR 6.1 (95% CI, 1.73-22, P = 0.004, Pc = 0.05), and when compared with a control group of non-venom subjects, 43% vs 16%, OR 3.9 (95% CI, 1.72-9.0, P = 0.002, Pc = 0.02). The 44 wasp-sensitive patients had an increase in the DRB1*11 allele when compared with the control subjects, 13% vs 6%, with an OR 2.2 (95% CI, 1.0-4.6, P = 0.04, Pc = NS), and a decreased prevalence of DRB1*04 alleles, 10% vs 19%, with an OR 0.33 (95% CI, 0.24-0.99, P = 0.04, Pc = NS), but these were not significant when multiple comparisons were taken into account. The DPB1 alleles were not significantly different between the venom sensitive patients and the controls.

CONCLUSION

Patients monosensitive to bee venom had a significantly greater prevalence of DRB1*07 alleles than the non-venom, control population suggesting that IgE responses in these patients may, in part be controlled by immune response HLA class II genes. These results are also suggestive of wasp-sensitive patients having a higher prevalence of DRB1*11 and a lower prevalence of DRB1*04 than the control population.

Snake bites in Kenya: a preliminary survey of four areas

Primary data were collected on the incidence, severity and species responsible for snake bites in 4 areas of Kenya: (i) Kakamega and western Kenya, (ii) Lake Baringo and Laikipia, (iii) Kilifi and Malindi, and (iv) northern Kenya. The overall average frequency of snake bite was 13.8 per 100,000 population per year (range 1.9-67.9). The minimum rate of snake bite mortality was 0.45/100,000/year. Thirty-four of the 50 units visited reported no knowledge of death from snake bite in the last 5 years. Possible reasons for the low estimates are discussed. Traditional treatments were common, especially the use of herbal remedies and incisions at the wound site.

Snakebite by the bushmaster (Lachesis muta) in Brazil: case report and review of the literature

The bushmaster (Lachesis muta) of Central and South America, the world's longest pit viper, is capable of injecting a large dose of potent venom when it bites. A 28-year-old man, bitten by a 1.82 m long L. m. muta in Brazil, developed pain and oedema at the bite site, nausea, vomiting, diarrhoea and sweating. There was peripheral neutrophil leucocytosis and evidence of fibrinogen consumption with secondary activation of the fibrinolytic system. Two hours after the bite, eight ampoules of Instituto Butantan Lachesis antivenom was administered, and haemostasis was normal 24 hr later. A review of reports of 20 cases of bites in humans reliably attributed to this snake in Costa Rica, French Guiana, Brazil, Colombia and Venezuela confirms a syndrome of nausea, vomiting, abdominal colic, diarrhoea, sweating, hypotension, bradycardia and shock, possibly autopharmacological or autonomic in origin, not seen in victims of other American crotaline snakes. These, and other symptoms of bushmaster envenoming, are explained by haemorrhagic, coagulant and neurotoxic venom activities. The therapeutic efficacy of non-specific Bothrops/Crotalus polyvalent antivenoms in these cases has been unimpressive. For the treatment of bites by a snake which potentially injects a large dose (> 300 mg dry weight) of venom with a range of life-threatening activities, there is an urgent need to develop more potent specific antivenoms and to treat the dramatic and life-threatening cardiovascular symptoms.

The effect of antibody against TNF alpha on cytokine response in Jarisch-Herxheimer reactions of louse-borne relapsing fever

Severe Jarisch Herxheimer reaction (J-HR) precipitated by antibiotic treatment of louse-borne relapsing fever (LBRF) is associated with a transient, marked rise in circulating tumour necrosis factor alpha (TNF alpha), interleukin 6 (IL-6) and interleukin 8 (IL-8). Ovine polyclonal anti-TNF alpha antibody fragments (Fab) were used in a randomized double blind placebo controlled trial in an attempt to prevent this reaction. Within 4 h after penicillin, in controls (n = 29), a several-fold rise in cytokines occurred, concomitant with a fall in spirochaetes and maximal clinical manifestations of the J-HR. An intravenous infusion of anti-TNF alpha Fab, 30 min before penicillin in 20 patients reduced peak plasma levels of IL-6 and IL-8 (but not IL-1 beta) compared with controls (p = 0.01 and < 0.001, respectively) and the incidence of the J-HR, indicating some neutralization of TNF alpha. An apparent fall in TNF alpha reflected interference of anti-TNF alpha in the immunoassay.

First clinical experiences with a new ovine Fab Echis ocellatus snake bite antivenom in Nigeria: randomized comparative trial with Institute Pasteur Serum (Ipser) Africa antivenom

During the past decade, effective snake antivenoms have become scarce in northern Nigeria. As a result, many patients severely envenomed by the saw-scaled or carpet viper (Echis ocellatus), which is responsible for more than 95% of the snake bites in the region, did not receive effective treatment and mortality and morbidity increased. To combat this crisis, a new monospecific ovine Fab antivenom (EchiTab) is being developed. Its theoretical advantages over conventional equine F(ab')2 antivenom are a more rapid tissue penetration and larger apparent volume of distribution (the volume of [tissue] fluid in which the the antivenom would be uniformly distributed to achieve the observed plasma concentration). In a preliminary study, two vials (20 ml; 1.0 g of protein) of EchiTab rapidly and permanently restored blood coagulability and cleared venom antigenemia in seven envenomed patients. Four experienced early reactions that responded to epinephrine. In a randomized comparative trial of one vial (10 ml; 0.5 g protein) of EchiTab or four ampules (40 ml; 2.12 g of protein) of Institute Pasteur Serum (Ipser) Africa polyspecific F(ab')2 antivenom, there were fewer reactions, but only 36% and 35% of patients, respectively, showed permanent restoration of coagulability, with the remainder requiring further doses. This suggests that 0.5 g (one vial) of EchiTab is approximately equivalent to 2.12 g (four ampules) of Ipser Africa antivenom, and that a higher initial dose will be required for most patients. Measurements of circulating venom and antivenom levels reflected the clinical events.

Synopsis of recent developments in venomous snake systematics

Changes to our understanding of venomous snake systematics, and the consequent changes in the nomenclature of these animals, have traditionally been a great source of confusion among biomedical researchers. This paper aims to facilitate access to the taxonomic literature by presenting a synopsis of the changes in venomous snake systematics that have taken place recently (primarily since 1992), together with some comments on the implications of these changes for toxinologists and clinicians. Some long-standing problems in venomous snake taxonomy receive special attention. This includes Asiatic Naja, Asiatic Agkistrodon/Gloydius, Bothrops and related genera, Trimeresurus, Echis, Daboia (including Daboia russellii) and Vipera. It is hoped that this synopsis will result in the use of a more up-to-date and interpretable nomenclature for venomous snakes in the toxinological literature.

Severe cytomegalovirus infection in immunocompetent patients

Severe cytomegalovirus (CMV) infection is rare in previously healthy immunocompetent individuals; to our knowledge, only thirty-four such cases have been reported in the worldwide literature. Multiorgan involvement was associated with a high mortality rate among these patients. Disease that clinically involves only the liver or lungs could be fatal; in contrast, none of the patients with isolated central nervous system infection died. Although few patients were treated with specific antiviral therapy, five of six patients with severe infection recovered after receiving therapy with ganciclovir or foscarnet. The rarity of severe CMV disease in immunocompetent patients probably precludes the performance of a clinical trial to evaluate the efficacy of specific antiviral therapy. However, the historically poor prognosis in the absence of such therapy suggests that rapid diagnosis of CMV disease and early instigation of specific treatment may be important.

Visual loss in immunocompetent patients with Cryptococcus neoformans var. gattii meningitis

In Papua New Guinea cryptococcal meningitis occurs predominantly in immunocompetent patients in whom Cryptococcus neoformans var, gattii is implicated in 95% of cases. Ocular complications are common. We have reviewed ophthalmic findings in 82 immunocompetent patients and have attempted to identify those features of the disease that predict an unfavourable visual outcome. Visual loss occurred in 52.6% of survivors and was associated with optic atrophy following optic disc swelling in 60.9%. Progression of disc swelling to optic atrophy was predicted by the presence of an abducens palsy (P = 0.049) and cerebrospinal fluid (CSF) cryptococcal antigen titres > 1:1024 (P = 0.036). Raised intracranial pressure (defined as opening CSF pressure > or = 300 mm on admission) was not associated with visual loss. Vision deteriorated in 17.3% of patients despite anticryptococcal therapy and in 3.7% it followed curative therapy. The high rate of visual loss in immunocompetent patients with C. neoformans var. gattii infection contrasts with others' experience of immunosuppressed patients with C. neoformans var. neoformans infection, in whom visual loss was rare. This difference may reflect immune mediated optic nerve dysfunction in C. neoformans var. gattii meningitis caused by either compression due to arachnoid adhesions or oedema and inflammatory cell-mediated damage.

Tetrodotoxic poisoning from ingestion of a porcupine fish (Diodon hystrix) in Papua New Guinea: nerve conduction studies

Near Port Moresby in Papua New Guinea, three of four adult family members who ate a porcupine fish (Diodon hystrix) were severely poisoned. Within one hour of the meal, both the mother and her older daughter had developed paraesthesiae, ataxia, hypersalivation, sweating, and had collapsed and died. The younger daughter developed similar symptoms with progressive paralysis requiring mechanical ventilation for 24 hr, but she made a complete recovery 10 days after the poisoning. In this patient, nerve conduction studies showed reduced sensory and motor conduction velocities and evoked amplitudes with gradual improvement in parallel with the patient's clinical condition, consistent with the known action of tetrodotoxin on voltage-gated sodium channels.

The effect of corticosteroids on visual loss in Cryptococcus neoformans var. gattii meningitis

In Papua New Guinea visual loss is a frequent sequal to Cryptococcus neoformans var. gattii meningitis in immunocompetent patients. We have previously postulated that visual loss may occur as a result of the immunological response to infection around the optic nerve. This retrospective study set out to explore the effect of corticosteroids on visual outcome. Sixteen patients received varying doses of corticosteroid (mainly 100-250 mg of hydrocortisone daily for the prevention of febrile reactions to amphotericin) and 10 received anticryptococcal therapy alone. Visual deterioration occurred less frequently in those treated with corticosteroids (2/16 [12.5%] vs. 7/10 [70%], P = 0.007), blindness was less frequent (1/16 [5.3%] vs. 5/10 [50%], P = 0.018), and in 3 patients vision improved. Corticosteroids may have a role in preventing or halting visual loss in C. neoformans var. gattii meningitis in immunocompetent patients.

Cell-mediated immunity in HIV seronegative patients recovered from Cryptococcus neoformans var. gattii meningitis

Cell-mediated immunity was assessed in 37 HIV seronegative healthy patients cured of Cryptococcus neoformans var. gattii meningitis and compared with matched controls using a multitest device which simultaneously injects seven standardized common antigens intradermally. Responses in patients and controls were similar: however, male patients had significantly higher compound (average) scores than controls (P = 0.041). Male scores were higher than female scores in both patient (P = 0.002) and control (P = 0.017) groups. In eight patients with acute cryptococcal meningitis, seven were anergic to challenge with 5 IU of tuberculin on admission. Two of these patients had positive reactions after treatment. Three of four patients tested prior to treatment with the multitest device were anergic to all seven antigens but all three survivors showed improved responsiveness following cure. These data suggest that patients are immunosuppressed on presentation (due to overwhelming var. gattii infection) but that following cure, cell-mediated immunity improves to its premorbid state. A transient state of immunosuppression prior to the development of the disease cannot be excluded.

Exposure to Cryptococcus neoformans var. gattii--a seroepidemiological study

An enzyme-linked immunosorbent assay was developed to study prevalence of immunoglobulin G (IgG) antibody to non-capsular Cryptococcus neoformans var. gattii antigen in a population of healthy Papua New Guinea (PNG) controls and patients. Patients with acute C. neoformans var. gattii meningitis had elevated levels of IgG which declined significantly following treatment (P = 0.034). Levels in the sera of convalescent patients were significantly higher than those in PNG controls (P < 0.001), which in turn were significantly higher than in a UK control group (P < 0.001). Clear differences were observed amongst the PNG controls. Adults had significantly higher levels than children (P = 0.002) and men had significantly higher levels than women (P = 0.047). No difference was observed between levels in patient-related and unrelated controls. IgG responses in PNG controls mirror the prevalence of disease in this population. It is postulated that exposure to C. neoformans var. gattii is less common in children and women due to some as yet unidentified behavioural difference and that exposure occurs away from the home environment.

Prevention of Jarisch-Herxheimer reactions by treatment with antibodies against tumor necrosis factor alpha

BACKGROUND

In patients with louse-borne relapsing fever (Borrelia recurrentis infection), antimicrobial treatment is often followed by sudden fever, rigors, and persistent hypotension (Jarisch-Herxheimer reactions) that are associated with increases in plasma concentrations of tumor necrosis factor alpha (TNF-alpha), interleukin-6, and interleukin-8. We attempted to determine whether sheep polyclonal Fab antibody fragments against TNF-alpha (anti-TNF-alpha Fab) could suppress the Jarisch-Herxheimer reaction.

METHODS

We conducted a randomized, double-blind, placebo-controlled trial in 49 patients with proven louse-borne relapsing fever. Immediately before the intramuscular injection of penicillin, the patients received an intravenous infusion of either anti-TNF-alpha Fab or a control solution.

RESULTS

Ten of the 20 patients given anti-TNF-alpha Fab had Jarisch-Herxheimer reactions with rigors, as compared with 26 of the 29 control patients (P = 0.006). The controls had significantly greater mean maximal increases in temperature (1.5 vs. 0.8 degrees C, P < 0.001), pulse rate (31 vs. 13 per minute, P < 0.001), and systolic blood pressure (25 vs. 15 mm Hg, P < 0.003), as well as higher mean peak plasma concentrations of interleukin-6 (50 vs. 17 micrograms per liter) and interleukin-8 (2000 vs 205 ng per liter) (P < 0.001 for both comparisons). Levels of TNF-alpha were undetectable after treatment with anti-TNF-alpha Fab.

CONCLUSIONS

Pretreatment with sheep anti-TNF-alpha Fab suppresses Jarisch-Herxheimer reactions that occur after penicillin treatment for louse-borne relapsing fever, reduces the associated increases in plasma concentrations of interleukin-6 and interleukin-8, and may be useful in other forms of sepsis.

Severe and complicated falciparum malaria in Melanesian adults in Papua New Guinea

Severe falciparum malaria usually occurs in children, but also occurs in nonimmune migrants or partially immune adults in areas of unstable transmission. We have studied prospectively 70 adult patients with strictly defined severe malaria from the south coast of Papua New Guinea where malaria transmission is not intense. Only 19 (27.1%) were migrants from areas where malaria transmission does not occur; many other patients were periurban dwellers who had become infected after visits to their home villages. The most common clinical features were jaundice or hepatic dysfunction, impaired consciousness, renal failure, cerebral malaria, and anemia. Hypoglycemia was common following treatment with quinine. The overall case fatality rate was 18.6%; renal failure and cerebral malaria in particular were associated with a poor outcome. Reduction in mortality might be achieved by aggressive therapy of renal failure with earlier institution of dialysis; the use of preventive measures for immigrants or urban dwellers returning to high transmission areas might reduce the incidence of this dangerous disease.

The emerging syndrome of envenoming by the New Guinea small-eyed snake Micropechis ikaheka

The New Guinea small-eyed or ikaheka snake, Micropechis ikaheka, which occurs throughout New Guinea and some adjacent islands, is feared by the indigenes. The first proven human fatality was in the 1950s and this species has since been implicated in many other cases of severe and fatal envenoming. Reliable attribution of envenoming to this species in victims unable to capture or kill the snake recently became possible by the use of enzyme immunoassay. Eleven cases of proven envenoming by M. ikaheka, with two fatalities, were identified in Papua New Guinea and Irian Jaya. Five patients showed no clinical signs of envenoming. The other six patients showed symptoms typical of envenoming by other Australasian elapids: mild local swelling, local lymphadenopathy, neurotoxicity, generalized myalgia, spontaneous systemic bleeding, incoagulable blood and passage of dark urine (haemoglobinuria or myoglobinuria). Two patients developed hypotension and two died of respiratory paralysis 19 and 38 h after being bitten. In vitro studies indicate that the venom is rich in phospholipase A2, is indirectly haemolytic, anticoagulant and inhibits platelets, but is not procoagulant or fibrinolytic. It shows predominantly post-synaptic neurotoxic and myotoxic activity. Anecdotally, Commonwealth Serum Laboratories' (CSL) death adder antivenom has proved ineffective whereas CSL polyvalent antivenom may be beneficial. Anticholinesterase drugs might prove effective in improving neuromuscular transmission and should be tested in patients with neurotoxic envenoming.

Predictors of outcome in Cryptococcus neoformans var. gattii meningitis

In Papua New Guinea, Cryptococcus neoformans var. gattii meningitis has a high fatality rate even in immunocompetent patients. Our retrospective study attempted to identify marker of poor prognosis. Of 88 immunocompetent patients, 30 (34.1%) died, usually soon after admission, and mortality was higher in men (p = 0.025) and older patients (p = 0.039). Death was associated with altered consciousness (p < 0.001), a history of convulsions prior to treatment (p = 0.002) and a maximum systolic blood pressure of > 150 mmHg (p = 0.017). These data suggest that death results from raised intracranial pressure and subsequent tentorial herniation. However, CSF opening pressure measured on admission was raised in 29/36 (81%) patients and did not predict outcome. In survivors, relapse was uncommon and was not predicted by discharge serum cryptococcal antigen titres, which were frequently raised on completion of therapy in asymptomatic patients. Mortality may be reduced if efforts are made to lower intracranial pressure in those patients who present with markers of poor prognosis.

High incidence of bites and stings by snakes and other animals among rubber tappers and Amazonian Indians of the Juruá Valley, Acre State, Brazil

Among forest-dwelling Amazonian Indians and rubber tappers (seringueiros) of the Juruá valley in Acre State, north-western Brazil, snakebite is an important cause of morbidity and death. Overall, 13% of a surveyed population had been bitten during their lifetime. Seventeen per cent of Katukina Indians, but only 8% of Ashaninkas, had been bitten by snakes reflecting, perhaps, different levels of traditional knowledge of the forest and its dangers. Most bites occurred in the jungle or on jungle trails (56%), while people were working (41%) or walking (26%), and were inflicted on the feet (54%). Ninety per cent of bite victims received treatment, usually traditional (93%); the majority (80%) recovered fully. Mortality was estimated at about 400 deaths per 100,000 population per lifetime. Bites and stings from other venomous forest and river animals, especially the freshwater sting ray (Potamotrygon sp.), were also extremely common. One death from an ant bite was recorded.

Neurotoxicity, anticoagulant activity and evidence of rhabdomyolysis in patients bitten by death adders (Acanthophis sp.) in southern Papua New Guinea

Thirty-two patients with enzyme-immunoassay-proven death adder (Acanthophis sp.) bites were studied in Port Moresby, Papua New Guinea. Eighteen were envenomed; local signs were rare and none had incoagulable blood, but all except one had signs of neurotoxicity. Five (27.7%) envenomed patients required intubation and ventilation. One patient developed renal failure, previously undescribed following death adder bites. Laboratory investigations showed mild prolongation of prothrombin and partial thromboplastin times in some patients. In vitro studies showed that the venom contains anticoagulant activity, but does not cause fibrinogenolysis. In contrast to taipan envenoming, neurotoxicity did not progress after antivenom administration, and there was reversal of neurotoxicity, evident within 6 h, in three severely envenomed patients treated less than 12 h after the bite. One patient treated with antivenom and anticholinesterases had the most dramatic response to treatment; the optimum management of bites by this species may include prompt treatment with both antivenom and anticholinesterases in addition to effective first aid.

Meningitis caused by Cryptococcus neoformans var. gattii and var. neoformans in Papua New Guinea

Eleven cases of cryptococcal meningitis were diagnosed and biotyped from September 1991 to August 1992 in Papua New Guinea (PNG). Seven isolates were Cryptococcus neoformans var. gattii from paediatric and adult patients, one with diabetes mellitus and 4 were C. neoformans var. neoformans from adults, of whom 2 had human immunodeficiency virus type 1 (HIV-1) infection, and one each had tuberculosis and Plasmodium vivax malaria. Significant clinical findings were headache, fever, meningism, vomiting, photophobia, papilloedema and cranial nerve lesions. Five patients (45.5%) died; 3 of these were adults with var. gattii and 2 were men with both var. neoformans and HIV-1 infections. This prospective tropical study documents the emergence of C. neoformans var. neoformans in patients with HIV-1 infection in a country where previously var. gattii had predominated in the immunocompetent. There has been no earlier report of cryptococcosis in an HIV-1 seropositive patient in PNG. Despite presumed exposure to both varieties of C. neoformans, var. gattii infections had been most frequent. As HIV-1 spreads, the proportion of hosts infected with var. neoformans may rise. The course of meningitis caused by the 2 varieties of C. neoformans may differ, with mortality in the tropics remaining particularly high. In PNG the environmental source of C. neoformans remains elusive.

Neuromuscular effects of Papuan Taipan snake venom

Snakebite is a cause of significant morbidity in Central Province, Papua New Guinea. Three adult patients with clinical evidence of neurotoxicity following envenomation by the Papuan taipan had serial neurophysiological examinations over the course of their subsequent hospitalization. All required artificial ventilation for 2.5 to 5 days. The compound muscle action potential (CMAP) amplitudes declined over the first 2 to 4 days after envenoming and then gradually increased in parallel with clinical recovery. Repetitive stimulation studies revealed a distinctive pattern of abnormality. Activation resulted in brief potentiation of the CMAP followed by significantly greater decrement than observed at rest. This effect lasted up to 30 minutes and was not altered after intravenous edrophonium. Single-fiber electromyographic recordings during the recovery phase of the illness were abnormal with marked blocking and increased jitter. All patients were able to return home.

Evaluation of atovaquone in the treatment of patients with uncomplicated Plasmodium falciparum malaria

The activity of atovaquone in patients with oligosymptomatic Plasmodium falciparum malaria was assessed in an open, non-comparative clinical study. The patients showed a good clinical response, but there was a high rate of recrudescence. The activity of atovaquone in combination with another antimalarial agent should be investigated.

Electrophysiological findings in patients envenomed following the bite of a Papuan taipan (Oxyuranus scutellatus canni)

Electrophysiological studies were done on patients with systemic neurotoxicity following the bite of a Papuan taipan (Oxyuranus scutellatus canni). Evoked compound muscle action potentials decreased and increased in tandem with clinical deterioration and recovery. Nerve conduction velocities did not change in envenomed patients and were consistent with control studies. Repetitive nerve stimulation studies showed decremental responses in envenomed patients with post-tetanic potentiation followed by post-tetanic exhaustion. The findings are consistent with studies in vitro which suggested that the major action of neurotoxins in Australian taipan venom is at the synapse. The observation that electrophysiological data correlate closely with the clinical condition of the patient has potential application in the assessment of interventions in the management of snake bite victims.

Failure of 3,4-diaminopyridine and edrophonium to produce significant clinical benefit in neurotoxicity following the bite of Papuan taipan (Oxyuranus scutellatus canni)

Progressive systemic neurotoxicity is a common feature in patients envenomed following the bite of a Papuan taipan (Oxyuranus scutellatus canni). Respiratory paralysis, which commonly results, accounts for considerable morbidity and mortality. Established neurotoxicity does not respond to antivenom. In this study, a combination of clinical and electrophysiological variables was used to assess the effect of edrophonium and 3,4-diaminopyridine in patients with significant neurotoxicity. Both drugs produced minor electrophysiological and clinical changes in envenomed patients. This effect was maximal when the 2 drugs were used in combination, but was insufficient to be of significant clinical benefit. Neither drug can be recommended for use in the management of Papuan taipan bite.

Human rabies: a continuing challenge in the tropical world

More than 99% of all human rabies deaths in the world occur in tropical developing countries. In India alone, 30,000 to 50,000 people may die of rabies each year. The Lyssaviruses (Family Rhabdoviridae) include rabies and rabies-related viruses, 3 of which have caused human disease. Rabies is a zoonosis, principally affecting domestic and stray dogs in most parts of Africa, Asia and Latin America. In North America, southern Africa, parts of the Caribbean and Europe, the principal mammalian reservoir species are wild carnivores. The pathogenesis, clinical features and differential diagnosis of rabies are discussed. The planning of rabies control strategies requires background information on the distribution and incidence of rabies in animals and the species involved. In some parts of the world, such as Latin American cities, most domestic dogs, even apparent strays, have an owner and can be immunized with conventional canine vaccines during well publicized campaigns. However, in areas such as India, where there may be a high proportion of stray domestic dogs without owners, and in those areas where wild mammals are the principal reservoir species, immunization may be possible using live attenuated or recombinant oral vaccines distributed in baits. In the poor tropical developing countries, unsatisfactory nervous tissue vaccines are still widely used. However, economical multisite intradermal regimens using tissue culture vaccines have proved effective and have begun to replace nervous tissue vaccines in some countries.