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Malaria transmission in rennell, solomon islands
37
MICROBIOLOGY
PROFICIENCY OF MALARIA DIAGNOSIS
Dr John Walker, Department of Parasitology, Westmead Hospital, Westmad, N.S.W. 2145 Malaria is the most c m n s p e c i f i c a l l y t r o p i c a l p a r a s i t i c disease imported into m y developed nations, including Australia. The correct c l i n i c a l management of m a l a r i a infections depends on accurate recognition of the species irivolved. Fran data gathered by the r e g i s t e r of cases maintained i n N ew South Wales i t is apparent that around 20% of smies identifications are-kong. Most importantly, 25% of a l l diagnoses involving Plasrodium f a l c i p a m are incorrect. The reasons f o r these diagnostic errors are m y . They include inadequate staining of blood films, excessive periods between collection of the blood and the making of films, a disinclination on the part of m y laboratories t o use thick blood films and, probably most importantly, lack of experience.
The situation could be inproved by adoption of sinple, effective staining methods and the organisation of s p e c i f i c workshaps on malaria diagnosis.
AUSTRALIAN AEMY MALARIA RESEWCH UNIT K. Rieckmann, Amy Malaria Research U n i t , University
of Sydney, Ingleburn, N.S.W.
2174
Research a c t i v i t i e s a t the Unit are directed mainly towards the development and evaluation of drugs and drug regimens f o r the prophylaxis and treatment of drug-resistant m a l a r i a . Although mst investigations involve Plasmodium f a l c i m , P. v i v a is receiving more attention following the U n i t ' s docmentation that scme strains have become resistant t o chloroquine. Novel approaches developed by the Unit have led t o the evaluation of proguanil/dapsone (low dose) and doxycycline/primaquine f o r malaria prophylaxis. Both drug canbinations have been very effective in controlling malaria during preliminary field studies. The doxycycline/primaquine regimen appears t o have the added advantage of providing protection (not only suppression) against vivax malaria. If this is confirmed by further studies, it w i l l no longer be necessary t o take the mnbersome primaquine eradication course a f t e r likely exposure to malaria. The U n i t is also involved i n characterizing the drug resistance pattern of malaria parasites in the southwest Pacific area. The drug susceptibility of parasites can be determined i f heparinised blood specimens, collected before treatment, are received by the Unit within 24 hours of their collection. Such information would be of benefit in the c l i n i c a l management of malaria patients.
MALARIA TRANSMISSSION IN RENNELL, SOLOMON ISLANDS S R W e i n s t e i n , " P a t l l o l o y y D e p t , Gold Coast H o s p i t a l , Nerany S t , Southport. Queensland 4215 The Polynesian outlier of t h e Solomons, Rennell Island ( p o p . 1 5 0 0 1 i s c o n s i d e r e d to h a v e a l o n e r i n c i d e n c e of m a l a r i a than o t h e r endemic a r e a s o f Lhe Solomons. Prior t o DDT o p r a y i n y s i n 19'10-1 and 1900. a p a r a s i t e r a t e of 7 . 6 % and p r e s e n c e of t h e A n o p h e l e s f o r n u t i v e c t o r were d e s c r i b e d , w i t h t r a n s m i s s i o n s u b s e q u e n t l y t h o u y l i t L o be i n t e r r r u p t e d . TO t e s t this, 2 2 2 p e o p l e c o m p r i s i n g t h e m a j o r i t y of the p o p u l a t i m of 3 village were s u r v e y e d by f i n g e r s t i c k i n Feb/March 1 9 8 3 . T h i c k and t h i n smfa1-s were p r e p a r e d i n t h e f i e l d and p o s i t i v e s c o n f i r m e d by t h e 11110 T e c h n i c a l O C f i c e r and M a l a r i o l o y i s t i n lioninra.
oositives were d e t e c t e d : 0 m a l e s (47%). 9 ca-dium f a l c i o a r u m c a s e s (58%). and 7 t o t a l p n r n s i l e r a t e of 7 . 7 % . Aye r a n g e was 1 - 4 3 . 3 c a s e s ( 1 0 y e a r s , 9 c a s e s 11-20 y e a r s , 2 c a s e s 2 1 - 3 0 y e a r s and 3 c a s e s > 3 1 . Only two had a h i s t o r y o f t r a v e l to o t h e r endemic a r e a s . Seventeen (171 fcniales (5391:
i0
..___ P . v i v a x ( 4 1 % ) . makiiig a
The f i n d i n g o f m a l a r i a i n p e o p l e who had n o t t r a v e l l e d to o t h e r i s l a n d s i n t h e Solonions s u g g e s t s l o c a l t r a n s m i s s i o n by a low i n c i d e n c e v e c t o r . The number of R e n n e l l e s e l i v i n g on o t h e r e n d e m i c i s l a n d s and t r a v e l l i n g home m i o h t s e r v e 3 s a s o u r c e . P r e s e n t e r : S t e p h e n W e i l l s t e i n . Gold C o a s t l l o s p i t a l
INFECTIONS IN TRANSPLANT PATIENTS J.L. HARKNESS Department of Microbiology,St.Vincent's Hospita1,Sydney 1nfection.s are a serious complication that may follow any organ transplant. The degree of immunosuppression and the period of time after transplantation determine the infection likely to be present. Bacterial infections occur early and may follow any organ transplant. After bone marrow transplantation bacteraemia is confirmed in up to 50% of patients during the early neutropenic phase. Response rates are satisfactory if therapy is initiated early. The Hickman's catheter is a common source of bacteraemia with L a u r e u s and S . e n i d e r m i d i ~ the most frequently isolated pathogens. Infections occurring in the months following organ transplantation include salmonella septicaemia, pneumococcal pneumonia, staphylococcal sepsis, haemophilus pulmonary disease, listeriosis, legionella pneumonia and occasionally mycobacterial disease. Pulmonary nocardiosis has been a problem particularly in cardiac transplant recipients. Herpes viruses may cause significant morbidity and mortality in s imDlex reactivates early and is transplant recipients. HerDes effectively controlled by oral acyclovir. Cytomegalovirus (CMV) infections occur 1-3 months post transplant and CMV pneumonitis is often fatal. Preliminary results suggest prophylactic ganciclovir is effective in controlling CMV disease. may occur later and is treated with acyclovir. Candida albicans oropharyngitis and oesophagitis are common in the early phase whilst systemic infections caused by b e r e i l l u s spp, F u s a r i u n u and members of the order Mucorales occur at a later stage and usually require invasive procedures for definitive diagnosis. Parasitic infections include Pneumocvstis carin1 . ..1 pneumonia (PCP), Toxoplasma eondii myocarditis and pneumonitis and occasionally giardiasis, amoebiasis and strongyloidiasis. Prevention of PCP with cotrimoxazole or dapsone has been very successful. Prophylaxis for other parasitic infections is not warranted in view of their infrequent occurrence.
MICROBIOLOGY
PROFICIENCY OF MALARIA DIAGNOSIS
Dr John Walker, Department of Parasitology, Westmead Hospital, Westmad, N.S.W. 2145 Malaria is the most c m n s p e c i f i c a l l y t r o p i c a l p a r a s i t i c disease imported into m y developed nations, including Australia. The correct c l i n i c a l management of m a l a r i a infections depends on accurate recognition of the species irivolved. Fran data gathered by the r e g i s t e r of cases maintained i n N ew South Wales i t is apparent that around 20% of smies identifications are-kong. Most importantly, 25% of a l l diagnoses involving Plasrodium f a l c i p a m are incorrect. The reasons f o r these diagnostic errors are m y . They include inadequate staining of blood films, excessive periods between collection of the blood and the making of films, a disinclination on the part of m y laboratories t o use thick blood films and, probably most importantly, lack of experience.
The situation could be inproved by adoption of sinple, effective staining methods and the organisation of s p e c i f i c workshaps on malaria diagnosis.
AUSTRALIAN AEMY MALARIA RESEWCH UNIT K. Rieckmann, Amy Malaria Research U n i t , University
of Sydney, Ingleburn, N.S.W.
2174
Research a c t i v i t i e s a t the Unit are directed mainly towards the development and evaluation of drugs and drug regimens f o r the prophylaxis and treatment of drug-resistant m a l a r i a . Although mst investigations involve Plasmodium f a l c i m , P. v i v a is receiving more attention following the U n i t ' s docmentation that scme strains have become resistant t o chloroquine. Novel approaches developed by the Unit have led t o the evaluation of proguanil/dapsone (low dose) and doxycycline/primaquine f o r malaria prophylaxis. Both drug canbinations have been very effective in controlling malaria during preliminary field studies. The doxycycline/primaquine regimen appears t o have the added advantage of providing protection (not only suppression) against vivax malaria. If this is confirmed by further studies, it w i l l no longer be necessary t o take the mnbersome primaquine eradication course a f t e r likely exposure to malaria. The U n i t is also involved i n characterizing the drug resistance pattern of malaria parasites in the southwest Pacific area. The drug susceptibility of parasites can be determined i f heparinised blood specimens, collected before treatment, are received by the Unit within 24 hours of their collection. Such information would be of benefit in the c l i n i c a l management of malaria patients.
MALARIA TRANSMISSSION IN RENNELL, SOLOMON ISLANDS S R W e i n s t e i n , " P a t l l o l o y y D e p t , Gold Coast H o s p i t a l , Nerany S t , Southport. Queensland 4215 The Polynesian outlier of t h e Solomons, Rennell Island ( p o p . 1 5 0 0 1 i s c o n s i d e r e d to h a v e a l o n e r i n c i d e n c e of m a l a r i a than o t h e r endemic a r e a s o f Lhe Solomons. Prior t o DDT o p r a y i n y s i n 19'10-1 and 1900. a p a r a s i t e r a t e of 7 . 6 % and p r e s e n c e of t h e A n o p h e l e s f o r n u t i v e c t o r were d e s c r i b e d , w i t h t r a n s m i s s i o n s u b s e q u e n t l y t h o u y l i t L o be i n t e r r r u p t e d . TO t e s t this, 2 2 2 p e o p l e c o m p r i s i n g t h e m a j o r i t y of the p o p u l a t i m of 3 village were s u r v e y e d by f i n g e r s t i c k i n Feb/March 1 9 8 3 . T h i c k and t h i n smfa1-s were p r e p a r e d i n t h e f i e l d and p o s i t i v e s c o n f i r m e d by t h e 11110 T e c h n i c a l O C f i c e r and M a l a r i o l o y i s t i n lioninra.
oositives were d e t e c t e d : 0 m a l e s (47%). 9 ca-dium f a l c i o a r u m c a s e s (58%). and 7 t o t a l p n r n s i l e r a t e of 7 . 7 % . Aye r a n g e was 1 - 4 3 . 3 c a s e s ( 1 0 y e a r s , 9 c a s e s 11-20 y e a r s , 2 c a s e s 2 1 - 3 0 y e a r s and 3 c a s e s > 3 1 . Only two had a h i s t o r y o f t r a v e l to o t h e r endemic a r e a s . Seventeen (171 fcniales (5391:
i0
..___ P . v i v a x ( 4 1 % ) . makiiig a
The f i n d i n g o f m a l a r i a i n p e o p l e who had n o t t r a v e l l e d to o t h e r i s l a n d s i n t h e Solonions s u g g e s t s l o c a l t r a n s m i s s i o n by a low i n c i d e n c e v e c t o r . The number of R e n n e l l e s e l i v i n g on o t h e r e n d e m i c i s l a n d s and t r a v e l l i n g home m i o h t s e r v e 3 s a s o u r c e . P r e s e n t e r : S t e p h e n W e i l l s t e i n . Gold C o a s t l l o s p i t a l
INFECTIONS IN TRANSPLANT PATIENTS J.L. HARKNESS Department of Microbiology,St.Vincent's Hospita1,Sydney 1nfection.s are a serious complication that may follow any organ transplant. The degree of immunosuppression and the period of time after transplantation determine the infection likely to be present. Bacterial infections occur early and may follow any organ transplant. After bone marrow transplantation bacteraemia is confirmed in up to 50% of patients during the early neutropenic phase. Response rates are satisfactory if therapy is initiated early. The Hickman's catheter is a common source of bacteraemia with L a u r e u s and S . e n i d e r m i d i ~ the most frequently isolated pathogens. Infections occurring in the months following organ transplantation include salmonella septicaemia, pneumococcal pneumonia, staphylococcal sepsis, haemophilus pulmonary disease, listeriosis, legionella pneumonia and occasionally mycobacterial disease. Pulmonary nocardiosis has been a problem particularly in cardiac transplant recipients. Herpes viruses may cause significant morbidity and mortality in s imDlex reactivates early and is transplant recipients. HerDes effectively controlled by oral acyclovir. Cytomegalovirus (CMV) infections occur 1-3 months post transplant and CMV pneumonitis is often fatal. Preliminary results suggest prophylactic ganciclovir is effective in controlling CMV disease. may occur later and is treated with acyclovir. Candida albicans oropharyngitis and oesophagitis are common in the early phase whilst systemic infections caused by b e r e i l l u s spp, F u s a r i u n u and members of the order Mucorales occur at a later stage and usually require invasive procedures for definitive diagnosis. Parasitic infections include Pneumocvstis carin1 . ..1 pneumonia (PCP), Toxoplasma eondii myocarditis and pneumonitis and occasionally giardiasis, amoebiasis and strongyloidiasis. Prevention of PCP with cotrimoxazole or dapsone has been very successful. Prophylaxis for other parasitic infections is not warranted in view of their infrequent occurrence.