Biology & control of Anopheles culicifacies Giles 1901.

Malaria epidemiology is complex due to multiplicity of disease vectors, sibling species complex and variations in bionomical characteristics, vast varied terrain, various ecological determinants. There are six major mosquito vector taxa in India, viz. Anopheles culicifacies, An. fluviatilis, An. stephensi, An. minimus, An. dirus and An. sundaicus. Among these, An. culicifacies is widely distributed and considered the most important vector throughout the plains and forests of India for generating bulk of malaria cases (>60% annually). Major malaria epidemics are caused by An. culicifaices. It is also the vector of tribal malaria except parts of Odisha and Northeastern states of India. An. culicifacies has been the cause of perennial malaria transmission in forests, and over the years penetrated the deforested areas of Northeast. An. culicifacies participates in malaria transmission either alone or along with An. stephensi or An. fluviatilis. The National Vector Borne Disease Control Programme (NVBDCP) spends about 80 per cent malaria control budget annually in the control of An. culicifacies, yet it remains one of the most formidable challenges in India. With recent advances in molecular biology there has been a significant added knowledge in understanding the biology, ecology, genetics and response to interventions, requiring stratification for cost-effective and sustainable malaria control. Research leading to newer interventions that are evidence-based, community oriented and sustainable would be useful in tackling the emerging challenges in malaria control. Current priority areas of research should include in-depth vector biology and control in problem pockets, preparation of malaria-risk maps for focused and selective interventions, monitoring insecticide resistance, cross-border initiative and data sharing, and coordinated control efforts for achieving transmission reduction, and control of drug-resistant malaria. The present review on An. culicifacies provides updated information on vector biology and control outlining thrust areas of research.

Mosquito-borne diseases in Assam, north-east India: current status and key challenges.

Mosquito-borne diseases, including malaria, Japanese encephalitis (JE), lymphatic filariasis and dengue, are major public health concerns in the north-eastern state of Assam, deterring equitable socioeconomic and industrial development. Among these, malaria and JE are the predominant infections and are spread across the state. The incidence of malaria is, however, gradually receding, with a consistent decline in cases over the past few years, although entry and spread of artemisinin-resistant Plasmodium falciparum remains a real threat in the country. JE, formerly endemic in upper Assam, is currently spreading fast across the state, with confirmed cases and a high case-fatality rate affecting all ages. Lymphatic filariasisis is prevalent but its distribution is confined to a few districts and disease transmission is steadily declining. Dengue has recently invaded the state, with a large concentration of cases in Guwahati city that are spreading to suburban areas. Control of these diseases requires robust disease surveillance and integrated vector management on a sustained basis, ensuring universal coverage of evidence-based key interventions based on sound epidemiological data. This paper aims to present a comprehensive review of the status of vectorborne diseases in Assam and to address the key challenges.

Study of Incidence, Laterality and Patency of the Posterior Condylar Canal In 100 Dry Human Skulls.

Background: The posterior condylar foramina are the largest of the emissary foramina’s present in the human skull. The posterior condylar canal transmits the posterior condylar emissary vein and it acts as a route for venous circulation between extracranial venous system and intracranial venous sinuses. It also acts as a channel for spread of infection. Due to its varied clinical implications and to get a better knowledge about the canal this study was taken up. Objectives: To determine the variations in the occurrence of posterior condylar canalwith respect to incidence, laterality, patency and if patent whether intrasinus or retrosinus. Materials and methods: An observational study was carried out on 100 dry human skulls obtained from the department of anatomy, Kempegowda Institute Of Medical Sciences, Bangalore, India. The posterior condylar canal was observed and noted. The patency was ascertained by passing a probe and care was taken to note whether the canal opened intrasinus or retrosinus. Result: The posterior condylar canal was found to be present in 90% of the skulls. The incidence of bilateral presence was more than the unilateral presence. 82.22% of the canals were patent with the intrasinus type being themost prevalent. Conclusion: The knowledge of the posterior condylar canal and its variations is important for the radiologist, neurosurgeons, ENT surgeons operating in this area.

Dengue, an emerging arboviral infection in Assam, northeast India

Dengue is emerging as major public health concern in northeast India and spreading with increased morbidity. Most cases were recorded in Guwahati metropolitan city of the state of Assam during post-monsoon months (September- December). These comprised all age groups of both sexes with significantly higher incidence of cases in adult males aged 26– 60 years.

Dengue vectors in urban and suburban Assam, India: entomological observations.

Background: Dengue is rapidly becoming established in north-east India and spreading, on account of rapid urbanization and population movement, with reported morbidity and attributable death cases. This study aims to determine the seasonal abundance of Aedes (Stegomyia) albopictus and Aedes (Stegomyia) aegypti in Guwahati metropolis and suburban settlements; to characterize the breeding resources for these mosquitoes; and to ascertain the status of their susceptibility to adulticides and larvicides. Methods: Mosquito larval surveys were carried out in different localities in both Guwahati city and adjoining suburbs from January to December 2013, to determine the seasonal abundance of disease vectors and their breeding preferences. The insecticide susceptibility status of mosquito adults and larval populations of both Aedes aegypti and Aedes albopictus was ascertained, using World Health Organization standard diagnostic concentrations and test procedures. Results: The study revealed that both Aedes aegypti and Aedes albopictus are widely abundant in Guwahati city and suburbs, and breeding in a wide variety of resources. Aedes albopictus, however, was the predominant mosquito species in suburbs, breeding preferentially in flower vases, cut-bamboo stumps and leaf axils. Aedes aegypti was the most common in the city, breeding predominantly in discarded tyres, cement tanks and used battery boxes. Both Aedes aegypti and Aedes albopictus were resistant to dichlorodiphenyltrichloroethane (DDT; 4%), but susceptible to malathion (5%), and exhibited a varied response to pyrethroids. However, larval populations of both these mosquito species were susceptible to larvicides, including malathion (1.0 mg/L), temephos (0.02 mg/L) and fenthion (0.05 mg/L), at much lower dosages than diagnostic concentrations. Conclusion: Given the seasonal abundance and case incidence in city areas, it is highly probable that Aedes aegypti is the predominant mosquito vector transmitting dengue virus. The study results have direct relevance for the state dengue-control programme, for targeting interventions and averting outbreaks and spread of disease.

Transmission of malaria and its control in the northeastern region of India.

Let alone the eradication, malaria control itself has amounted to be a challenge, and is detrimental to the all round development of the northeastern region of India. Focal outbreaks are frequent taking heavy tool on human lives. Plasmodium falciparum is the predominant parasite species and is solely responsible for increased morbidity and mortality. The region contributes bulk of P. falciparum cases for the rest of India, and its proportions are increasing. Efficient vectors like Anopheles minimus, Anopheles fluviatilis and Anopheles dirus persistently support transmission of malaria. The present review gives a comprehensive account of the factors responsible for transmission of the disease with focus on vector bionomics, its prevention and control.

Multicentric clinical trials for safety and efficacy evaluation of alpha;beta arteether in complicated P. falciparum malaria.

OBJECTIVE: To evaluate efficacy of alpha;beta arteether in patients of P. falciparum malaria presenting with complications was undertaken in a multicentric clinical trial. METHOD: Each patient who consented to undergo clinical trial with parenteral Arteether was treated with a fixed dose schedule of Arteether given intramuscularly in a dose of 150 mg once a day on three consecutive days. Every patient was followed upto 28 days with clinical, haematological and parasitological monitoring every day upto one week and thereafter at 14, 21 and 28 days. The response was assessed in terms of fever clearance time, parasite clearance time, cure rate and parasite reappearance rate. RESULTS: A total of 211 patients of P. falciparum malaria were included in the study from four centres (Bhilai, Guwahati, Jamshedpur and Rourkela). Results of this study showed that fever clearance time ranged between 24-168 hours, parasite clearance time ranged between 24-120 hours and overall mortality ranged between 4-8.5%. Out of 211, only 14 patients expired during the study, of these, 10 patients expired within first two days i.e. before completing the three day schedule of arteether therapy. Tolerability to arteether injection was good in all these patients and no untoward effects were experienced or reported during the study. Overall cure rate observed in these studies was 93%. CONCLUSION: This study shows a rapid parasite and fever clearance in patients of complicated P. falciparum malaria.

Morbidity and mortality due to malaria in Tarajulie Tea Estate, Assam, India.

Beginning 1991, a sudden rise of malaria cases were recorded in Tarajulie TE (Assam) coupled with mortality due to malaria. Deaths were confirmed due to Plasmodium falciparum (Pf) infections and were recorded in all age groups excluding infants. Malaria positives were recorded in all months of the year, however, there was a increased hospital attendance due to fever/malaria positives during May to September. During the years (1991-1993), the slide positive rate was as high as 33.04%, mostly being Pf infections (69%), and the annual parasite index ranged between 6 to 304 per thousand population. Morbidity and mortality due to malaria were attributed to labor movements to and fro from garden premises to adjoining hamlets, the latter being the site of acquisition of the infections.

Susceptibility of Plasmodium falciparum to chloroquine in tea garden tribes of Assam, India.

P. falciparum was the predominant parasite ( > 80%) species in malaria ridden tea estates of Assam. A simplified 3 day in vivo test to determine chloroquine sensitivity in tea garden tribes revealed that the majority of the cases (85%) were S/RI, 7% were RI, and 3% were RII and 5% were RIII, respectively. Early case detection and treatment were deemed necessary to reduce morbidity and mortality due to P. falciparum in these tea estates.

A follow up study of major intimal dissections treated with perfusion balloon catheter.

Major intimal dissections during coronary angioplasty are an important cause of early morbidity and mortality. In the recent past various non-surgical modalities to manage such dissections have been developed. The choice of therapy among these needs knowledge not only of immediate success but also of long term results. Data on long term follow up of patients managed with prolonged balloon inflations using a perfusion balloon catheter is limited. We herein report our experience of twenty seven consecutive patients managed by prolonged dilatations using Stack perfusion balloon catheter. All the patients had a long dissection with luminal compromise, 6 (22%) had in addition an acute complete occlusion, and in 4 (15%) there was a thrombus. Only 6 (22%) needed an emergency CABG, with the remaining having an event free hospital stay. At follow up after 6-26 months, 7/21 (33%) had severe symptoms and 5 of them underwent coronary arteriography with four having a repeat successful dilatation. The findings of this study suggest that the perfusion balloon catheter is a useful modality for management of major dissections with a restenosis rate similar to that of primary PTCA. Randomised controlled trials are required to assess its efficacy vis a vis the newer therapeutic options like stents, lasers and atherectomy.

High-risk coronary angioplasty using percutaneous cardiopulmonary bypass support.

BACKGROUND. Balloon angioplasty has a high success rate but results in abrupt closure of the vessel in 2% to 6% of patients. This can lead to haemodynamic collapse and death, particularly if the patient has poor left ventricular function. In the event of abrupt closure of the coronary vessels, such patients may not survive long enough to undergo emergency bypass surgery. The prophylactic use of cardiopulmonary bypass to support patients at high-risk for angioplasty has been reported recently. We describe our initial experience with this technique. METHODS. Eighteen high-risk patients with severe angina were subjected to balloon angioplasty after instituting percutaneous cardiopulmonary bypass support to enhance the safety of high-risk elective coronary angioplasty. All patients had a low ejection fraction, a large amount of viable myocardium perfused by the targeted artery or both (left ventricular ejection fraction < 25% in 13 patients). Triple-vessel disease was present in all of them. Angioplasty of the only remaining vessel was done in 12 patients, 2 vessels in 5 patients and a sequential graft in 1 patient. Bypass flow ranged from 2.8 to 4.5 litres and was discontinued after a mean of 35 minutes. Haemostasis was achieved by external clamp compression in 16 patients. RESULTS. The angioplasty was successfully performed in all the patients and was well tolerated. During the bypass period, the pulmonary artery diastolic pressure ranged from 0 to 8 mmHg. There was no hospital death. Two patients required surgical exploration of the femoral artery puncture site--one because of poor distal perfusion and the other for continued bleeding. During the follow up period of 1 to 10 months, 11 patients were free of angina and 1 had died. CONCLUSION. Our experience confirms that percutaneous bypass support in selected patients undergoing high-risk coronary angioplasty is safe and effective.

Arrhythmias and conduction defects in patients with mitral valve prolapse: a study based on ambulatory monitoring and electrophysiologic studies.

Twenty consecutive symptomatic patients of mitral valve prolapse (MVP) and 20 normal age, sex and symptom matched controls were studied. Ambulatory monitoring studies revealed the presence of atrial premature beats (APC) in 16 subjects in each group. Isolated ventricular premature beats (VPC) were observed in 12 patients with MVP and 15 subjects in control group (p = ns). Complex VPCs (Lown IVa, IVb) were recorded in 4 patients of MVP vs 3 controls (p = ns). There was no correlation between the occurrence of arrhythmias with the degree of MVP or the degree of mitral regurgitation. Likewise, MVP patients with prolonged QTc interval did not show higher incidence of spontaneous arrhythmias when compared to those with normal QTc interval. Nineteen patients underwent electrophysiological studies. Two patients showed evidence of abnormal sinus node function. Both these patients in addition had AV nodal abnormalities, manifested by prolonged AH interval. Programmed stimulation studies induced AV nodal tachycardia in one and non-sustained ventricular tachycardia in two (polymorphic in one and monomorphic in the other). Ambulatory monitoring in both these patients did not show any evidence of complex VPCs or VT, indicating poor correlation between inducibility and presence of spontaneous complex VPCs. Patients with MVP do not have a higher prevalence of spontaneous atrial or ventricular arrhythmias when compared to matched normal controls with similar symptomatology. The presence of mitral regurgitation, severity of MVP and associated prolonged QTc interval is not associated with higher prevalence of arrhythmias. The correlation between spontaneous and inducible arrhythmias is poor.(ABSTRACT TRUNCATED AT 250 WORDS)

High risk coronary angioplasty using percutaneous cardiopulmonary bypass support.

Twenty high risk patients with severe angina were subjected to balloon angioplasty after instituting percutaneous cardiopulmonary bypass support to enhance the safety of high risk elective coronary angioplasty. All patients had a low ejection fraction, a large amount of viable myocardium perfused by the targeted artery or both (left ventricular ejection fraction < or = 25% in 15 patients). Three vessel disease was present in all. Angioplasty of the only remaining vessel was done in 14 patients, 2 vessels in 5 patients and a sequential graft in 1 patient. Bypass flows ranged from 2.8-4.5 litres. Bypass was discontinued after a mean bypass time of 35 min. Haemostasis was achieved by external clamp compression in 16 patients. The angioplasty was successfully performed in all the patients and the procedure was well tolerated. During the bypass period the pulmonary artery diastolic pressures ranged from 0-8 mm Hg. There was 1 hospital death due to abrupt vessel closure. Two patients required surgical help to repair femoral artery. During the follow up period of 1-12 months, 67% patients have no angina and only 1 has died. Our experience demonstrates the safety and efficacy of percutaneous bypass support in selected patients undergoing high risk coronary angioplasty.

Angioplasty of total coronary occlusions using combination of intracoronary Probing Catheter and balloon on wire Probe.

We describe our experience with a technique for PTCA of total coronary occlusions using the ultra low profile balloon on wire Probe. An intracoronary Probing Catheter was used to facilitate crossing the stenosis with a guide wire. This was followed by exchanging the guide wire for the Probe into the obstruction for balloon dilatation. This technique was used in 22 consecutive patients undergoing PTCA for chronic total occlusion. The total obstruction could be crossed by guide wire (0.014 flex or 0.016 standard) passed through Probing Catheter in 19 patients (86%). The obstruction could be successfully dilated by the Probe, delivered through the probing catheter, in 17 of these patients. Of the remaining 2 patients, one could be dilated by sequential dilatation using over the wire low profile balloon system and the other one by dilatation with the Probe, respectively. The Probing Catheter technique offers a new method to apply balloon on wire technology to the dilatation of chronic total coronary occlusions with very promising results.

Congenital complete heart block in structurally normal heart--a study of 44 cases.

Data of 44 patients with congenital complete heart block and structurally normal heart have been analysed. Thirty one patients were asymptomatic (group I) and 13 patients had symptoms of low cerebral perfusion like syncope, near syncope or convulsions (group II). A ventricular rate on surface ECG was found to be significantly lower in the symptomatic group (56.7 +/- 13.2 beats per minute, bpm, in group I and 46.5 +/- 6.0 bpm in group II). Similarly wide QRS escape rhythm of greater than 0.10 seconds was more often seen in group II (2/13) as compared to group I (2/31) though the difference did not reach statistical significance. Presence of pauses of more than 3.0 seconds on ambulatory ECG monitoring were infrequent in both the groups (group I 1/7, group II 2/7), however more often seen in group II. Electrophysiological studies carried out in 11 patients were not helpful in differentiating the two groups and all the patients including two with a wide QRS escape rhythm on surface ECG showed suprahisian level of block. The corrected junctional recovery time in two groups did not show any statistical difference. A persistently slow ventricular rate of less than 50 bpm during waking hours, wide QRS escape rhythm and pauses of greater than 3 seconds on ambulatory monitoring are suggestive of high risk to the patient and may justify implantation of permanent pacemaker even in asymptomatic patients.