Emergence of Schoengastiella ligula as the vector of scrub typhus outbreak in Darjeeling: Has Leptotrombidium deliense been replaced.

Background: Following a suspected outbreak of scrub typhus in Kurseong, Darjeeling, the Armed Forces Medical College, Pune was requested by the National Institute of Epidemiology and the State authorities to undertake investigation of the ongoing scrub typhus outbreak and suggest containment measures. Materials and Methods:The epidemic team undertook clinical, entomological and serological studies to understand the local disease pattern and delineate high risk areas, host diversity by rodent trapping using Sherman traps, mite fauna diversity, abundance and vector species identification by phase contrast microscopy for preparation of electronic database and rodent and human serological studies by Weil Felix and PCR. Results:The results indicate no association of scrub typhus with age and sex (P=0.37 and 0.74 respectively). The maximum cases occurred amongst the tea garden workers (73%) in the age group of 25-44 years. The predominant clinical presentation was fever (100%) with headache (75%), lymphadenopathy (45%) and presence of eschar (76.7%). The dominant host species (50% of trapped rodents) was shrew Suncus murinus, the index animal for scrub typhus, which contributed maximally to the vector abundance (52.96%) with a chigger index of 61.56. The trombiculid mite Schoengastiella ligula was the vector species much against the expected mite vector Leptotrombidium deliense, in the area. The study found the presence and abundance of vector species which corroborated well with the occurrence of cases in the various localities within the subdivisions. Conclusion:The study thus establishes Schoengastiella ligula as the vector of scrub typhus outbreak in Kurseong, Darjeeling. Preventive and containment measures with emphasis on reduction of man - vector contact were suggested to the state authorities to contain the outbreak.

Immune thrombocytopenic purpura.

Immune thrombocytopenic purpura (ITP) is the commonest cause of sudden onset thrombocytopenia in a healthy child. The condition is frequently preceded by a viral infection. The hematological parameters are essentially normal except a low platelet count. Bone marrow examination is not routinely indicated except in specific situations. The pros and cons of drug treatment have been discussed as the disease is benign with excellent prognosis in majority of the cases. The various treatment options including low and high dose steroids, intravenous immunoglobulins and anti D have been discussed at length with other modalities of treatment and role of splenectomy. Current therapeutic options with rituximab and other drugs for stimulating platelet production in chronic cases have also been included in discussion.

Myelodysplastic syndrome.

Pediatric myelodysplastic syndrome (MDS), though rare, constitutes a distinct entity quite different from adult MDS. They have unique clinical features, aggressive clinical course with an overall mean survival of only 9.9 months. A pediatric approach to the WHO classification has become necessary since the WHO classification of MDS has failed to address the uniqueness of pediatric MDS. A new prognostic system also needs to be evolved since the international prognostic system has limited prognostic impact in children. Intensive chemotherapy such as the one used in de novo-acute myeloid leukemia (AML) leads to complete remission in some children and this may be the treatment of choice in pediatric MDS.

A study of bone marrow failure syndrome in children.

Background: Bone marrow failure syndrome (BMFS), or aplastic anemia, includes peripheral blood single cytopenias, as well as pancytopenia due to inability of the marrow to effectively produce blood cells. Aim: To study the clinico-hematological profile and etiological factors of bone marrow failure syndrome in children. Setting and Design: This prospective study was carried out in the Department of Pediatrics of a university teaching hospital over 36 months. Materials and Methods: Children with pancytopenia (Hb 9 /L, platelet count < 100 x 10 9 /L) and bone marrow cellularity < 25% were included in the study. History of exposure to drugs, socioeconomic status, ethnicity and occupation of father were noted. Bone marrow aspiration; trephine biopsy; Ham test; viral studies for hepatitis A, B and C; and cytogenetic investigations were carried out. Statistical Analysis: Relative risk was estimated by odds ratio (OR) with 95% confidence interval (CI) in matched cases and controls. Results: Of the 53 children studied, 6 (11.3%) were diagnosed as Fanconi anemia. Two cases had features of myelodysplastic syndrome. Forty-five children were labeled as acquired aplastic anemia, of whom one had evidence of hepatitis B infection and two patients (5.8%) had paroxysmal nocturnal hemoglobinuria. Aplastic anemia was more common in children from family with lower socioeconomic status; in Muslims; and where the father's occupation was weaving, dyeing and painting. However, the number was small to make statistically significant conclusions. No correlation could be established with exposure to drugs. Conclusion: Fanconi anemia was responsible for approximately one-tenth of the cases of bone marrow failure syndrome. Majority of the patients had acquired aplastic anemia. Hepatitis B infection was an uncommon cause of acquired aplastic anemia.

Insecticide treated bednet strategy in rural settings: can we exploit women's decision making power?

Use of insecticide treated bednets in prevention of malaria is a widely propagated global strategy, however, its use has been reported to be influenced and limited by many variables especially gender bias. A cross sectional field epidemiological study was conducted in a rural setting with two outcome variables, 'Bednet use'(primary outcome variable) and 'Women's Decision Making Power' which were studied in reference to various predictor variables. Analysis reveals a significant effect on the primary outcome variable 'Bednet use' of the predictor variables- age, occupation, bednet purchase decision, women's decision making power, husband's education and knowledge about malaria and its prevention. The study recommends IEC on treated bednets to be disseminated through TV targeting the elderly women who have better decision making power and mobilizing younger women who were found to prefer bednets for prevention of mosquito bites for optimizing the use of treated bednets in similar settings.

Paroxysmal nocturnal hemoglobinuria in childhood: an uncommon presentation.

An eight year old boy presented with severe anemia and bleeding spots. Complete blood count showed pancytopenia. There was mild reticulocytosis. Bone marrow was hypocellular with normoblastic erythroid hyperplasia. Ham's test (acidified serum test) was positive which confirmed the diagnosis of Paroxysmal nocturnal hemoglobinuria (PNH). Although PNH is rare in childhood, it should be considered as a diagnostic possibility in cases of aplastic anemia as the two conditions can coexist. The presence of PNH in association with aplastic anemia can influence the outcome of the latter.

Efficacy of Fipronil and Propoxur in the control of German cockroaches (Dictyoptera: Blatellidae).

A field trial for comparative evaluation of chemicals Fipronil gel, Propoxur spray and bait was carried out. The results in the Fipronil treated area indicate a reduction of 89%, 100% and 98% in cockroach infestation by days 7, 30 and 60, whereas the reduction in Propoxur spray treated area during the same period was 88%, 91% and 87% respectively. Propoxur bait was not found to be effective in reducing the cockroach infestation; rather a build up of the cockroach infestation was noticed in the treated site. The study reports the efficacy of Fipronil gel treatment over conventional insecticidal formulations in the control of cockroach infestation in cookhouses of urban households.

Laboratory evaluation of repellents against Leptotrombidium deliense, vector of scrub typhus.

BACKGROUND & OBJECTIVES: Scrub typhus, a rickettsial disease transmitted by larvae of Leptotrombidium deliense, is of special importance to the Armed Forces personnel, due to the heightened risk to this disease during movement in mite endemic areas during exercise/war. The disease is best prevented by the use of personal protective measures including repellents. Studies were undertaken to determine the relative efficacy of repellents: diethyl toulamide (DEET), dibutyl phthalate (DBP) with an indigenously developed repellent diethyl phenyl acetamide (DEPA) against the larval trombiculid mite. METHODS: The repellents were tested for persistence on impregnated cloth prior to washing, post washing and ironing by means of a specially fabricated testing kit. Acaricidal efficacy estimation was performed on the treated fabrics and topical application efficacy of repellents on mice was evaluated by a novel animal testing model. RESULTS: DEET and DEPA were found to provide maximum protection (repellence and acaricidal efficacy), could withstand two launderings of the impregnated uniform and also had superior efficacy on topical application (8 h). Ironing was found to significantly reduce the repellence of DEET and DBP. INTERPRETATION & CONCLUSION: The findings of this study point towards the superiority of DEPA and DEET for impregnation of the uniform cloth as well as for topical application for the prevention of scrub typhus amongst the troops.

Primary orbital NHL--a rare entity, diagnosed on FNAC.

Primary Orbital NHL is a rare, malignant neoplasm of the orbit. FNAC is particularly useful for patients with such non-resectable, deep seated retroorbital tumors which are difficult to biopsy and in whom a firm cytologic diagnosis is vital to guide further treatment, such as radiotherapy and chemotherapy. A case of 70 years old female is described in the present article.

Pancytopenia--a clinico-hematologic analysis of 77 cases.

The present study was conducted in the department of Haematology and Transfusion Medicine, Government Medical College & Hospital, Chandigarh over a period of 32 months. During this period pancytopenia was an indication for bone marrow (aspiration and or trephine) in 77 out of a total of 205 cases (37.6%). The most common cause of pancytopenia as revealed by bone marrow was megaloblastic anaemia (68%) followed by aplastic anaemia (7.70%). This study also revealed few uncommon and rare, but interesting causes of pancytopenia like drug induced agranulocytosis, hemophagocytic syndrome and waldenstroms macroglobinemia.

Differential efficacy evaluation of formulations of Bacillus thuringiensis Var israelensis against mosquitoes: a laboratory investigation.

The efficacy evaluation of three formulations; wettable powder (W.P.) floating pellet and beads of Bacillus thuringiensis Var israelensis (Bti), revealed a greater susceptibility of the early larval instars of mosquitoes to Bti, sensitivity of anophelines to floating pellet, culicines to bead and equal efficacy and faster kill of W.P. to all the mosquitoes tested. A greater persistence of the slow release formulations, floating pellet and beads for 49 and 28 days against anophelines and culicines respectively was observed in contrast to a maximum persistence for 21 days in case of W.P. formulation.

Evaluation of some risk factors for ischaemic heart disease under a matched pairs case-control design.

A pair-wise matched case-control study was carried out in 200 male patients of ischaemic heart disease (IHD). The cases were matched with an equal number of controls in respect of the variables viz., age and socio-economic status. The objective was to quantify the risk of developing IHD for some of the leading risk factors under the univariate and multivariate situations. The analysis revealed that of the factors (smoking, overweight, hypertension, diabetes, serum cholesterol and family history) considered, the smoking habit of the individual, presence of family history of the disease and overweight were the significant risk factors responsible for the development of the disease. The estimated odds ratios were found to be 3.29, 2.60 and 2.00 respectively.

Epidemiological study of an outbreak of cholera in Delhi cantonment.

An epidemiological study was undertaken to investigate an outbreak of cholera in Delhi Cantonment during May 1991. The study design was a hybrid design using a retrospective Case-Control method superimposed on a population based cross-sectional approach. A total of 9 cases of cholera, confirmed in the laboratory as Vibrio cholerae, 0-1, Eltor, Ogawa were identified using population based survey and compared with 33 controls from the same source population. The overall Incidence rate was 0.71% and showed a significant rising trend with age. There was no morality. Assessment of water supply, sanitary conditions of cook houses and disposal system of night soil could not provide any clue to the source of infection. Subsequently, all the food handlers were subjected to rectal swab examination. Two of them, working in the same messes from where cases had occurred, were found positive for Vibrio cholerae (0-1, Eltor, Ogawa). Immediate control measures by way of isolation and treatment of carriers promptly abated the outbreak. Role of carriers in outbreak of cholera has been highlighted.