Do bedbugs transmit hepatitis B?

5 Sollid LM, Markussen G, Ek G, Gjerde H, Vartbal F, Thorsby E. Evidence for a primary association of celiac disease to a particular HLA-DQ &agr;/&bgr; heterodimer. J Exp Med 1989; 169: 345-50. 6 Lundin KEA, Scott H, Hansen T, et al. Gliadin-specific, HLADQ(&agr;1*0501,&bgr;1*0201) restricted T cells isolated from the small intestinal mucosa of celiac disease patients. J Exp Med 1993; 178: 187-96. 7 Gjertsen HA, Lundin KEA, Sollid LM, Eriksen JA, Thorsby E. T cells recognize a peptide derived from &agr;-gliadin presented by the celiac disease associated HLA-DQ (&agr;1*0501, &bgr;1*0201) heterodimer. Hum Immunol (in press). 8 Falchuk ZM, Gebhard RL, Sessoms C, Strober W. An in vitro model of gluten sensitive enteropathy. Effect of gliadin on intestinal epithelial cells of patients with gluten sensitivity enteropathy in organ culture. J Clin Invest 1974; 53: 487-500. 9 de Ritis G, Auricchio S, Jones HW, Lew EJ-L, Bernardin JE, Kasarda DD. In vitro (organ culture) studies of the toxicity of specific A-gliadin peptides in celiac disease. Gastroenterology 1988; 94: 41-49. 10 Wieser H, Belitz HD, Idar D, Ashkenzai A. Coeliac activity of gliadin peptides CT-1 and CT-2. Z Lebensm Unters Forsch 1986; 182: 115-17. 11 Kagnoff MR, Raleigh KA, Hubert JJ, Bernadin JF, Kasarda DD. Possible role of a human adenovirus in the pathogenesis of coeliac disease. J Exp Med 1984; 160: 1544-47. 12 Karagiannis JA, Priddle JD, Jewell DP. Cell-mediated immunity to a synthetic gliadin peptide resembling a sequence from adenovirus 12. Lancet 1987; i: 884-86. 13 Kasarda DD, Okita TW, Bernadin JE, et al. Nucleic acid (cDNA) and amino acid sequences of &agr;-type gliadins from wheat (Triticum aestivum). Proc Natl Acad Sci USA 1984; 81: 4712-16. 14 Chicz RM, Urban RG, Lane WS, et al. Predominant naturally processed peptides bound to HLA-DR1 are derived from MHC-

Do bedbugs transmit

15 16 17

18

19

20

21

22

23

24

related molecules and are heterogenous in size. Nature 1992; 358: 764-68. Patey AL, Evans DJ. Large scale preparation of gliadin proteins. J Sci Food Agric 1973; 24: 1229-93. Meeuwisse G. Diagnostic criteria in coeliac disease. Acta Paediatr Scand 1970; 59: 461-63. Ciclitira PJ, Evans DJ, Fagg NLK, Lennox ES, Dowling RH. Clinical testing of gliadin fractions in coeliac patients. Clin Sci 1984; 66: 357-64. Tatham AS, Marsh MN, Wieser H, Shewry PR. Conformational studies of peptides corresponding to the coeliac-activating regions of wheat &agr;-gliadin. Biochem J 1990; 270: 313-18. Brown JH, Jardetsky TS, Gorga JC, et al. Three-dimensional structure of the human class II histocompatibility antigen HLA-DR1. Nature 1993; 364: 33-39. Auricchio S, de Ritis G, Maiuri L, et al. A-gliadin related synthetic peptides: damaging effects on in vitro cultured atrophic coeliac intestinal mucosa and developing fetal rat intestine. Gastroenterology 1991; 100: A194. Wieser H, Blitz H-D, Ashkenazi A. Amino-acid sequence of the coeliac active gliadin peptice B3142. Z Lebensm Unters Forsch 1984; 179: 371-76. Ellis HJ, Doyle AP, Wieser H, Sturgess RP, Ciclitira PJ. Specificities of monoclonal antibodies to domain 1 of &agr;-gliadin. ScandJ Gastroenterol 1993; 28: 212-16. Mantzaris G, Jewell DP. In vivo toxicity of a synthetic dodecapeptide from A-gliadin in patients with coeliac disease. Scand J Gastroenterol 1991; 26: 392-98. Devery JM, Bender V, Penttila I, Skerritt JH. Identification of reactive synthetic gliadin peptides specific for coeliac disease. Int Arch Allergy Appl Immunol 1991; 95: 356-62.

hepatitis B?

Summary

Introduction

study was done over two years in seven Gambian villages to determine the contribution of bedbugs to hepatitis B transmission. In addition, fortnightly questionnaires were completed for each child to assess other possible routes of transmission. The intervention, insecticide spraying of the child’s dwelling, was highly effective in reducing exposure to bedbugs but there was no effect on hepatitis B infection. No other risk factor for transmission was identified despite a consistent village-to-village variation in the rate of childhood infection. The major mode of transmission of hepatitis B in childhood remains unknown.

Infection with hepatitis B virus occurs commonly in children aged 18 months to 10 years1 in sub-Saharan Africa. The risk is increased in those with infectious siblings, in infected households, and shows marked village-to-village variation.2 A number of routes of transmission have been proposed, including traditional scarring practices, injections, exudative skin lesions, and arthropods. There is little epidemiological evidence to support any of these but there is biological evidence to suggest that bedbugs (Cimex hemipterus) are a potential means of transmission: they carry infectious virus in the wild and continue to excrete virus for up to 6 weeks without re-exposure,3-5 and have shown an association with infected children positive for the e antigen.6 To establish the importance of bedbugs in the transmission of hepatitis B we did a randomised intervention trial in The Gambia.

An intervention

Lancet 1994; 343: 761-63

Subjects and methods International Agency for Research on Cancer (WHO), Banjul, The Gambia (M Vall Mayans MD, AJ Hall MRCP, H M Inskip PhD, J Chotard MD, M Mendy); and Medical Research Council Laboratories, The Gambia (S W Lindsay PhD, H C Whittle FRCP)

Correspondence to: Dr Andrew J Hall, Communicable Disease Epidemiology Unit, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK

A cross-sectional study was carried out of children aged 6 months to 5 years living in 7 adjacent Mandinka villages.6 88% of eligible children, as determined by a pre-survey census, attended. All children were examined by a physician, had a sample of blood taken for serology, and their beds examined for the presence of bugs. Children found to be uninfected (hepatitis B core antibody negative for children aged 12 months or older and hepatitis B surface antigen negative for those younger) were randomised into

761

an

intervention

90%

or

control group. The study was designed to have a 50% reduction in infection in the

power to detect

intervention group. Randomisation was by compound rather than individual because children frequently shared a bed and sometimes changed the bed they slept in within the compound. In intervention compounds, all mattresses, walls around the beds, bednets, and bed frames were sprayed every 4 months with permethrin (25% emulsifiable concentrate, Zeneca Public Health, London, UK) 0-5% solution at a rate of iL/25-50mZ. No side effects were observed or reported. Field assistants visited each household in the study every 2 weeks and questioned the mother or guardian of the child concerning sleeping arrangements and the use of locally bought insecticide. In addition, information was sought about risk factors for hepatitis B infection in the preceding fortnight. These included injections from any source, surgical operations, blood transfusions, and traditional practices such as clitoridectomy, circumcision, scarring, head shaving, and ear piercing. The field assistant also recorded the site and severity of any open skin lesions. Both treated and untreated compounds were regularly checked for the presence of bedbugs to assess the effectiveness of spraying. This was done by a ten person-minute search of the mattress before the next spray round. The presence of any bedbug led to beds being classified as positive, although the searcher could not be blinded to the intervention status of the household. After 2 years, a cross-sectional survey of study children was done. Each child was examined for active or healed tropical ulcers and their bed examined for the presence of bedbugs. A sample of blood was obtained by fingerprick. Serum was separated and tested for hepatitis B surface antigen by RPHA (Hepatest, Wellcome, London, UK) and for core antibody and e antigen by radioimmunoassay (Sorin, Sallugia, Italy). Infection was defined as seroconversion to hepatitis B core antibody positive. The study had the approval of both the joint Gambia Government/MRC ethics committee and the ethics committee of the International Agency for Research on Cancer (WHO). Analysis compared rates of infection in children in intervention compounds with rates in control compounds. Other possible risk factors for infection were examined similarly. Multiple logistic regression analyses were done to examine risk factors adjusted for the effect of other variables. A logistic regression model with random effects was also employed to take account of the fact that the unit of randomisation was the compound rather than the individual child.

Searches of beds showed both bedbugs and chicken ticks (Argas persicus). Insecticide spraying had a protective efficacy against infestation of mattresses of 88% (95% confidence interval [CI] 65 - 96%). 11-14% of children in unsprayed compounds slept in an infested bed. Infection with hepatitis B occurred in 30% of these children over the 2 years. The pattern of infection was similar to that found in the prevalence study with no differences by age or sex;6 in particular the same large,

statistically

significant

(p < 0-001)

village-to-village

variation was found (21-54%). The cumulative incidence of infection by treatment group is shown in the table. The protective efficacy against infection of insecticide spraying was 16% (-100-35%), an estimate unchanged when the analysis was limited only to children who had never spent more than 5 days away from their home compound. At the end of the study, no children in sprayed compounds had bedbugs in their beds and only 3 (1 %) had chicken ticks. In unsprayed compounds 31 (12%) children had bedbugs in their mattresses and 19 (7%) had ticks. There was no association between any marker of hepatitis B infection and the presence of bugs or ticks in the mattress. No child had a blood transfusion or an operation during the study and only 1 underwent scarification. Analysis of other factors was restricted to the 220 children with complete follow up. 15 children were circumcised and only 1 of these became infected (7%) compared with 60 (29%) of those not undergoing circumcision. 4 children had a "ganglion" removed and 1 became infected; 11 had their ears pierced of whom 3 (27%) became infected. Infected children had their heads shaved a mean of 2-75 times (1 97-353), whereas uninfected children were shaved 39 times (3-33-4-47). There was a slight excess of injections recorded by infected children: 0-82 (0-44-0-90) versus 0-66 (0-42-0-90) in uninfected children. No specific type of injection (health centre, chemist, traditional healer) showed any association with infection. Open skin lesions were recorded for five sites and graded into three grades of severity. These recordings were examined individually and as summary scores for the whole period. Only one statistically significant association was found: between infection and sores on the back of all severities (p 0 02). Tropical ulcers and ulcer scars examined at the end of the survey were not significantly associated with any hepatitis B marker (p>0-5). Multiple logistic regression analysis did not alter these results. The only variable associated with infection was the village of residence. The sex and age of the child, the mother’s hepatitis B status, and the number of older siblings known to be positive from the cross-sectional survey did not affect the risk of infection. The protective efficacy of spraying remained non-significant after adjustment for village (p 0 -2) with a point estimate of 20% (- 16-45%). The logistic regression analysis with random effects to take account of the unit of randomisation being the compound rather than the child gave a similar protective effect of spraying. =

Results There were 641 children in the survey who were uninfected with hepatitis B and randomised (320 to sprayed and 321 to unsprayed compounds). At the end of the intervention study 526 of these children were re-examined. 13 children had died, 3 refused to have a blood sample taken, and the remainder had left the village and could not be found. In sprayed compounds, 71 children were lost to follow up compared with 48 in unsprayed compounds (p 0-02). Of those re-examined there was complete fortnightly questionnaire information on 462, but only 220 children were available for skin examination at all of the 46 follow =

ups.

=

Discussion This study excludes bedbugs Figures in parentheses are percentages of column totals Table : Hepatitis B Infection amongst children after Intervention according to treatment of the compound

762

as the major mode of transmission of hepatitis B amongst Gambian children. It is unlikely that this negative finding is explained by study design or conduct, although the differential loss to follow up between intervention and control compounds is

unexplained.

No other factor was found to be associated with transmission in this study.- In particular, skin lesions showed no association, with a single exception out of numerous comparisons made. It seems likely that this finding is due to chance. The low incidence of traditional practices in this population coupled with a high incidence of infection make it unlikely that any of these play a major role in hepatitis B infection. It may be that hepatitis B is transmitted by a number of routes and that this study was not statistically powerful enough to detect any one of them. Alternatively there may be a major route of transmission that was not examined in this study. Salivary spread is the most likely candidate. No means of assessing this could be devised in the study. Anthropological studies of villages with large differences in transmission (greater than twofold) may offer a means of

generating hypotheses. The study indicates that behavioural change or the use of insecticide-treated bednets are unlikely to reduce the incidence of hepatitis B infection in childhood. Immunisation in infancy remains the best means of preventing infection7 and urgently needs to be introduced into the Expanded Programme on Immunisation of all countries in Africa.

This study

was supported by a grant from the Direzione Generale per la Cooperazione allo Sviluppo of the Ministry of Foreign Affairs of Italy. We thank the children and their families who participated in this study, the

field workers who collected information, and the MRC staff at Farafenni who provided support. We are also grateful for the assistance provided by the Medical and Health Department spray team, Zeneca Public Health for donation of permethrin, and to Ms S Cottrell for secretarial support. Dr L Tomatis, Dr X Bosch, and Dr C Muir of IARC were generous in their support and encouragement.

References 1

2

Barin F, Perrin J, Chotard J, et al. Cross-sectional and longitudinal epidemiology of hepatitis B in Senegal. Prog Med Virol 1981; 27: 148-62. Whittle HC, Inskip H, Bradley AK, et al. The pattern of childhood hepatitis B infection over 4 years in two Gambian villages. J Infect Dis

1990, 161: 1112-15. 3 4

5

6

Newkirk MM, Downe AER, Simon JB. Fate of infested hepatitis B

antigen in blood-sucking insects. Gastroenterology 1975; 69: 982-87. Jupp PG, McElingott SE. Transmission experiments with hepatitis B surface antigen and the common bedbug (Cimex lectularius L). S Afr Med J 1979; 56: 54-57. Ogston CW, Wittenstein FS, London WT, Millman I. Persistence of hepatitis B surface antigen in the bedbug Cimex hemipterus (Fabr). J Infect Dis 1979; 40: 411-14. Vall Mayans M, Hall AJ, Inskip HM, et al. Risk factors for transmission of hepatitis B virus to Gambian children. Lancet 1990; 336: 1107-09.

7

Fortuin M, Chotard J, Jack AD, et al. Efficacy of hepatitis B vaccine in the Gambian Expanded Programme of Immunisation. Lancet 1993; 341: 1129-31.

Short reports

Prophylaxis and reversal of ifosfamide encephalopathy with methylene-blue

The antineoplastic ifosfamide produces dose-dependent signs of neurotoxicity. After ifosfamide overdose in a patient, we found excessive urinary excretion of glutaric acid and sarcosine, which is compatible with glutaric aciduria type II, a defect in mitochondrial fatty acid oxidation that results from defective electron transfer to flavoproteins. We therefore used the electron-accepting drug methylene-blue as an antidote for ifosfamide encephalopathy. In one patient, ifosfamide neurotoxicity was rapidly reversed by methylene-blue 50 mg intravenously. In another patient with previous episodes of ifosfamide encephalopathy, methylene-blue was administered orally prophylactically. No symptoms of neurotoxicity were noted.

Lancet 1994; 343: 763-64

The mechanism of ifosfamide encephalopathy is unknown. Laboratory investigation of a patient who received an overdose of ifosfamide has revealed a possible explanation. A woman with metastatic sarcoma received ifosfamide 25 g intravenously over 24 h with mesna 20 g for uroprotection. The patient responded with sleepiness and reversible impairment of kidney function, recovering within a few days. Urinary glutaric acid excretion was 74 mmol on day 1 and 66 mmol on day 2 after drug administration (normal <0-02 mmol daily). Sarcosine

excretion was 0 78 and 0 45 mmol on these days (normal < 0’03 mmol). Glutaric aciduria is due to the absence of (type I) glutaryl-CoA dehydrogenase or (type II) of electrontransferring flavoproteins (ETF) or ETF complexes.2 Glutaric acid and sarcosine donate electrons to the respiratory chain via ETF and ETF-ubiquinone oxidoreductase complex and defects of ETF or the complex are typically associated with glutaric aciduria and sarcosinuria. Glutaric aciduria type Ihas been treated with methylene-blue3as an unphysiological electron acceptor that can restore the activity of glutaryl-CoA dehydrogenase and of other acyl-CoA dehydrogenases. With the same rationale, we have treated patients with acute or previous ifosfamide encephalopathy with methylene-blue. Patients with glutaric aciduria type IIrequire the administration of glucose to compensate for the derangements in fatty-acid oxidation and the accompanying deficiency of gluconeogenesis. The use of glucose in the infusion solutions was therefore an important supportive measure. An 18-year-old woman with metastatic osteosarcoma (lung and bone) began a 5 day chemotherapy regimen. Creatinine clearance was 52 mL/min. The cycle consisted of 12 g/m2 ifosfamide intravenously (days 1-5) with 8 g/m2 mesna (days 1-6) and doxorubicin 65 mg/m2 divided in two doses (days 1 and 2). She received intravenous ondansetron 8 mg. We used 5% glucose infusions (2 litres per 24 h). In addition, she received pyritinol 200 mg orally three times a day. On day 3, the patient had nightmares and signs of ifosfamide encephalopathy. 50 mg methylene-blue in a 2 % aqueous solution was administered by slow intravenous injection: after 30 min she became calm and coherent. About 4 h later, encephalopathy started to return. The methylene-blue was repeated and the signs of 763