Pericoronary adipose tissue attenuation on coronary computed tomography angiography associates with male sex and Indigenous Australian status

To evaluate if Indigenous Australians have higher coronary inflammation demonstrated non-invasively using pericoronary adipose tissue attenuation on coronary computed tomography angiography (CCTA). We retrospectively obtained a cohort 54 Indigenous patients age- and sex-matched to 54 non-Indigenous controls (age: 46.5 ± 13.1 years; male: n = 66) undergoing CCTA at the Royal Darwin Hospital and Monash Medical Centre. Patient groups were defined to investigate the interaction of ethnicity and sex: Indigenous + male, Indigenous + female, control + male, control + female. Semi-automated software was used to assess pericoronary adipose tissue attenuation (PCAT-a) and volume (PCAT-v). Males had significantly higher PCAT-a (- 86.7 ± 7.8 HU vs. - 91.3 ± 7.1 HU, p = 0.003) than females. Indigenous patients had significantly higher PCAT-v (1.5 ± 0.5cm3 vs. 1.3 ± 0.4cm3, p = 0.032), but only numerically higher PCAT-a (p = 0.133) than controls. There was a significant difference in PCAT-a and PCAT-v across groups defined by Indigenous status and sex (p = 0.010 and p = 0.030, respectively). Among patients with matching CCTA contrast density, multivariable linear regression analysis showed an independent association between Indigenous status and PCAT-a. Indigenous men have increased PCAT-a in an age- and sex-matched cohort. Male sex is strongly associated with increased PCAT-a. Coronary inflammation may contribute to adverse cardiovascular outcomes in Indigenous Australians, but larger studies are required to validate these findings.

Micronutrient Deficiency in Pregnancy: Time to Think Beyond Iron and Folic Acid Supplementation

BACKGROUND

Micronutrients play an important role in influencing pregnancy outcomes. Anemia is common among pregnant women against which iron and folic acid supplementation programs are already in action. The study aimed to estimate the prevalence of anemic and selected micronutrient status among pregnant women.

MATERIALS AND METHODS

It is a community-based cross-sectional study. The study was carried out among pregnant women registered in Primary Health Center, Kallur, Tirunelveli district, Tamil Nadu, India, using a semi-structured data capture tool. The blood samples were collected following standard procedure.

RESULTS

The micronutrient status among 139 pregnant women were selenium <1%, copper <1%, zinc 11.5%, iodine 14.4%, Vitamin B12 41.7%, and ferritin 42.4%. Vitamin B12, zinc, and selenium levels showed a significant difference with reference values among the three trimesters. Iron and folic acid supplementation was followed by 58.7% of pregnant women. Multiple micronutrient deficiency with anemia was found among 54.6%.

CONCLUSION

Anemia and micronutrient deficiency are high among pregnant women in this region. Since iron and folic acid supplementation strategies are already being implemented by the government, it is high time that we extend our health policy beyond that and plan for micronutrient supplementation as well.

Atherogenic index of plasma is associated with epicardial adipose tissue volume assessed on coronary computed tomography angiography

The atherogenic index of plasma (AIP) is a novel biomarker of atherogenic dyslipidaemia (AD), but its relationship with cardiac adipose tissue depots is unknown. We aimed to assess the association of AD with cardiac adipose tissue parameters on coronary computed tomography angiography (CCTA). We studied 161 patients who underwent CCTA between 2008 and 2011 (age 59.0 ± 14.0 years). AD was defined as triglyceride (TG) > 1.7 mmol/L and HDL < 1.0 mmol/L (n = 34). AIP was defined as the base 10 logarithmic ratio of TG to HDL. Plaque burden was assessed using the CT-Leaman score (CT-LeSc). We studied volume and attenuation of epicardial adipose tissue (EAT-v and EAT-a) and pericoronary adipose tissue (PCAT-v and PCAT-a) on CCTA using semi-automated software. Patients with AD had higher PCAT-v (p = 0.042) and EAT-v (p = 0.041). AIP was associated with EAT-v (p = 0.006), type II diabetes (p = 0.009) and male sex (p < 0.001) and correlated with CT-LeSc (p = 0.040). On multivariable analysis, AIP was associated with EAT-v ≥ 52.3 cm³, age, male sex and type II diabetes when corrected for traditional risk factors and plaque burden. AIP is associated with increased EAT volume, but not PCAT-a, after multivariable adjustment. These findings indicate AIP is associated with adverse adipose tissue changes which may increase coronary risk.

Radiomics-Based Precision Phenotyping Identifies Unstable Coronary Plaques From Computed Tomography Angiography

OBJECTIVES

The aim of this study was to precisely phenotype culprit and nonculprit lesions in myocardial infarction (MI) and lesions in stable coronary artery disease (CAD) using coronary computed tomography angiography (CTA)-based radiomic analysis.

BACKGROUND

It remains debated whether any single coronary atherosclerotic plaque within the vulnerable patient exhibits unique morphology conferring an increased risk of clinical events.

METHODS

A total of 60 patients with acute MI prospectively underwent coronary CTA before invasive angiography and were matched to 60 patients with stable CAD. For all coronary lesions, high-risk plaque (HRP) characteristics were qualitatively assessed, followed by semiautomated plaque quantification and extraction of 1,103 radiomic features. Machine learning models were built to examine the additive value of radiomic features for discriminating culprit lesions over and above HRP and plaque volumes.

RESULTS

Culprit lesions had higher mean volumes of noncalcified plaque (NCP) and low-density noncalcified plaque (LDNCP) compared with the highest-grade stenosis nonculprits and highest-grade stenosis stable CAD lesions (NCP: 138.1 mm3 vs 110.7 mm3 vs 102.7 mm3; LDNCP: 14.2 mm3 vs 9.8 mm3 vs 8.4 mm3; both Ptrend < 0.01). In multivariable linear regression adjusted for NCP and LDNCP volumes, 14.9% (164 of 1,103) of radiomic features were associated with culprits and 9.7% (107 of 1,103) were associated with the highest-grade stenosis nonculprits (critical P < 0.0007) when compared with highest-grade stenosis stable CAD lesions as reference. Hierarchical clustering of significant radiomic features identified 9 unique data clusters (latent phenotypes): 5 contained radiomic features specific to culprits, 1 contained features specific to highest-grade stenosis nonculprits, and 3 contained features associated with either lesion type. Radiomic features provided incremental value for discriminating culprit lesions when added to a machine learning model containing HRP and plaque volumes (area under the receiver-operating characteristic curve 0.86 vs 0.76; P = 0.004).

CONCLUSIONS

Culprit lesions and highest-grade stenosis nonculprit lesions in MI have distinct radiomic signatures compared with lesions in stable CAD. Within the vulnerable patient may exist individual vulnerable plaques identifiable by coronary CTA-based precision phenotyping.

Vascular inflammation in patients with obstructive sleep apnoea and coronary artery disease shown on coronary computed tomography angiography attenuation

Funding Acknowledgements

Type of funding sources: None.

Introduction

Obstructive sleep apnoea (OSA) is associated with increased plaque burden in coronary artery disease (CAD), but the role of vascular inflammation in this relationship is unclear. Coronary computed tomography angiography (CTA) enables surrogate assessment of systemic inflammation via subcutaneous adipose tissue attenuation (ScAT-a), and of coronary inflammation via epicardial adipose tissue volume and attenuation (EAT-v and EAT-a) and pericoronary adipose tissue attenuation (PCAT-a).

Purpose

To investigate whether vascular inflammation is increased in patients with severe OSA and high plaque burden.

Methods

Patients with clinically indicated polysomnography and coronary CTA were included. Severe OSA was classified as apnoea/hypopnoea index (AHI) &gt;30. High plaque burden was defined as a CT-Leaman score (CT-LeSc) &gt;8.3. Patients with both severe OSA and high plaque burden were defined as ‘Group 1’, all other patients were classified as ‘Group 2’. ScAT-a, EAT-a, EAT-v and PCAT-a were assessed on semi-automated software.

Results

A total of 91 patients were studied (59.3 ± 11.1 years). Severe OSA was associated with high plaque burden (p = 0.02). AHI correlated with CT-LeSc (r = 0.24, p = 0.023). Group 1 had lower EAT-a and PCAT-a compared to Group 2 (EAT-a: -87.6 vs. -84.0 HU, p = 0.01; PCAT-a: -90.4 vs. -83.4 HU, p &lt; 0.01). However, among patients without high plaque burden, EAT-a was increased in patients with severe OSA versus mild-moderate OSA (-80.3 vs. -84.0 HU, p = 0.020). On multivariable analysis, EAT-a independently associated with severe OSA and high plaque burden (p &lt; 0.02), and PCAT-a associated with severe OSA and high plaque burden, and hypertension (all p &lt; 0.01).

Conclusions

EAT attenuation is decreased in patients with severe OSA and high plaque burden but increased in patients with severe OSA and low plaque burden. These divergent results suggest coronary inflammation may be increased in OSA independent of CAD, but larger studies are required to validate these findings.

The Emerging Role of CT-Based Imaging in Adipose Tissue and Coronary Inflammation

A large body of evidence arising from recent randomized clinical trials demonstrate the association of vascular inflammatory mediators with coronary artery disease (CAD). Vascular inflammation localized in the coronary arteries leads to an increased risk of CAD-related events, and produces unique biological alterations to local cardiac adipose tissue depots. Coronary computed tomography angiography (CTA) provides a means of mapping inflammatory changes to both epicardial adipose tissue (EAT) and pericoronary adipose tissue (PCAT) as independent markers of coronary risk. Radiodensity or attenuation of PCAT on coronary CTA, notably, provides indirect quantification of coronary inflammation and is emerging as a promising non-invasive imaging implement. An increasing number of observational studies have shown robust associations between PCAT attenuation and major coronary events, including acute coronary syndrome, and 'vulnerable' atherosclerotic plaque phenotypes that are associated with an increased risk of the said events. This review outlines the biological characteristics of both EAT and PCAT and provides an overview of the current literature on PCAT attenuation as a surrogate marker of coronary inflammation.

Pericoronary Adipose Tissue Attenuation Is Associated with High-Risk Plaque and Subsequent Acute Coronary Syndrome in Patients with Stable Coronary Artery Disease

BACKGROUND

High-risk plaques (HRP) detected on coronary computed tomography angiography (CTA) confer an increased risk of acute coronary syndrome (ACS). Pericoronary adipose tissue attenuation (PCAT) is a novel biomarker of coronary inflammation. This study aimed to evaluate the association of PCAT with HRP and subsequent ACS development in patients with stable coronary artery disease (CAD).

METHODS

Patients with stable CAD who underwent coronary CTA from 2011 to 2016 and had available outcome data were included. We studied 41 patients with HRP propensity matched to 41 controls without HRP (60 ± 10 years, 67% males). PCAT was assessed using semi-automated software on a per-patient basis in the proximal right coronary artery (PCATRCA) and a per-lesion basis (PCATLesion) around HRP in cases and the highest-grade stenosis lesions in controls.

RESULTS

PCATRCA and PCATLesion were higher in HRP patients than controls (PCATRCA: -80.7 ± 6.50 HU vs. -84.2 ± 8.09 HU, p = 0.03; PCATLesion: -79.6 ± 7.86 HU vs. -84.2 ± 10.3 HU, p = 0.04), and were also higher in men (PCATRCA: -80.5 ± 7.03 HU vs. -86.1 ± 7.08 HU, p < 0.001; PCATLesion: -79.6 ± 9.06 HU vs. -85.2 ± 7.96 HU, p = 0.02). Median time to ACS was 1.9 years, within a median follow-up of 5.3 years. PCATRCA alone was higher in HRP patients who subsequently presented with ACS (-76.8 ± 5.69 HU vs. -82.0 ± 6.32 HU, p = 0.03). In time-dependent analysis, ACS was associated with HRP and PCATRCA.

CONCLUSIONS

PCAT attenuation is increased in stable CAD patients with HRP and is associated with subsequent ACS development. Further investigation is required to determine the clinical implications of these findings.

Pericoronary adipose tissue computed tomography attenuation distinguishes different stages of coronary artery disease: a cross-sectional study

AIMS

Vascular inflammation inhibits local adipogenesis in pericoronary adipose tissue (PCAT) and this can be detected on coronary computed tomography angiography (CCTA) as an increase in CT attenuation of PCAT surrounding the proximal right coronary artery (RCA). In this cross-sectional study, we assessed the utility of PCAT CT attenuation as an imaging biomarker of coronary inflammation in distinguishing different stages of coronary artery disease (CAD).

METHODS AND RESULTS

Sixty patients with acute myocardial infarction (MI) were prospectively recruited to undergo CCTA within 48 h of admission, prior to invasive angiography. These participants were matched to patients with stable CAD (n = 60) and controls with no CAD (n = 60) by age, gender, BMI, risk factors, medications, and CT tube voltage. PCAT attenuation around the proximal RCA was quantified per-patient using semi-automated software. Patients with MI had a higher PCAT attenuation (-82.3 ± 5.5 HU) compared with patients with stable CAD (-90.6 ± 5.7 HU, P < 0.001) and controls (-95.8 ± 6.2 HU, P < 0.001). PCAT attenuation was significantly increased in stable CAD patients over controls (P = 0.01). The association of PCAT attenuation with stage of CAD was independent of age, gender, cardiovascular risk factors, epicardial adipose tissue volume, and CCTA-derived quantitative plaque burden. No interaction was observed for clinical presentation (MI vs. stable CAD) and plaque burden on PCAT attenuation.

CONCLUSION

PCAT CT attenuation as a quantitative measure of global coronary inflammation independently distinguishes patients with MI vs. stable CAD vs. no CAD. Future studies should assess whether this imaging biomarker can track patient responses to therapies in different stages of CAD.

Pericoronary adipose tissue attenuation (PCAT) is associated with high-risk atherosclerotic plaque and subsequent acute coronary syndrome in patients with stable coronary artery disease

Background

High-risk plaque (HRP) features detected on computed tomography coronary angiography (CTCA) are associated with subsequent development of acute coronary syndrome (ACS). Pericoronary adipose tissue attenuation (PCAT) is a novel CT-derived non-invasive marker of coronary inflammation. The association between PCAT, HRP and outcomes is unknown.

Purpose

To evaluate the association between high-risk plaque HRP characteristics, ACS and PCAT attenuation as a surrogate marker of coronary inflammation.

Methods

Patients with stable chest pain referred for CTCA between 2011 and 2013 with outcome data were included. Patients with HRP were propensity matched to patients without HRP. PCAT-RCA and PCAT-lesion were assessed using semi-automated software (AutoPlaque version 2.0). PCAT-RCA was measured around the proximal 10–50 mm of the right coronary artery (RCA). PCAT-lesion was measured around the HRP or lesion with highest-grade stenosis in patients without HRP.

Results

78 patients (67±10 years, 67% males) included 41 (52.6%) patients with HRP. Median PCAT-RCA was higher in HRP patients than non-HRP patients (−80.4 HU [IQR −86.1, −76.5] vs. −86.3 HU [IQR −92.2, −77.0], p=0.02). PCAT-Lesion was not significantly different between HRP and non-HRP patients (−78.7 HU [IQR −84.4, −73.4] vs. −82.8 HU [IQR −91.1, −75.4], p=0.16). More patients with HRP developed a subsequent ACS (24.4% vs. 5.4%, p=0.008). HRP patients who experienced an ACS demonstrated a higher PCAT-RCA (−76.6 HU [IQR −81.3, −72.4] vs. −82.6 HU [IQR −87.4, −78.0], p=0.018) and PCAT-lesion (−74.3 HU [IQR −77.1, −68.4] vs. −80.7 HU [IQR −84.8, −74.9], p=0.04) compared to those who did not experience an ACS.

Conclusion

PCAT attenuation is elevated in stable CAD patients with HRP features. Measures of periarterial inflammation were also more evident in HRP patients who develop ACS, indicating a potential contribution to vulnerability. The implications for integration of these measures in clinical practice require further investigation.

Funding Acknowledgement

Type of funding source: None

Is there any perceptiveness about the mode of transmission of human immunodeficiency virus/acquired immune deficiency syndrome? An analysis among the adolescent tribal students in Tamil Nadu

Background:

Cognizance about human immunodeficiency virus (HIV) and acquired immune deficiency syndrome (AIDS) among the community is still lacking. Seldom studies done in tribal area and to indentify the awareness about HIV/AIDS among the adolescent tribal students in Jawadhu hills of Tamil Nadu, with the objectives includes on social, demographical, and knowledge about HIV/AIDS were taken. For primary data, survey method and secondary data from various literatures gathered.

Materials and Methods:

Schedule tribe adolescent students, between the age groups of 13–21 years, from 8^th to 12^th standard, exclusively from Vellore and Tiruvannamalai educational districts, were taken, by applying STRATA method.

Results:

A total of 938 students from various tribal schools participated. Amongst them, 507 (54%) were males and 431 (46%) were females. Half of the respondents (50%) agreed that blood transfusion, intravenous drug use, and sharing infected needles are the major modes of transmission. Nearly 35% agreed that HIV/AIDS is transmitted by hugging, tattooing, dirty hands, breastfeeding, kissing on cheeks, shaving at the barber shop, shaking hands with AIDS patients, homosexuality and are food and waterborne.

Conclusions:

Formal HIV/AIDS education should be mandatory in their curriculum, where teachers get an opportunity to deliver the scientific information about HIV/AIDS. To acquire better knowledge about HIV/AIDS, sex education should be included in the mainstream of curriculum with the assistance of educational consultants, professional social workers, and also local non-governmental organizations to conduct further mindfulness camps about the HIV/AIDS.

Myocardial Infarction Associates With a Distinct Pericoronary Adipose Tissue Radiomic Phenotype: A Prospective Case-Control Study

OBJECTIVES

This study sought to determine whether coronary computed tomography angiography (CCTA)-based radiomic analysis of pericoronary adipose tissue (PCAT) could distinguish patients with acute myocardial infarction (MI) from patients with stable or no coronary artery disease (CAD).

BACKGROUND

Imaging of PCAT with CCTA enables detection of coronary inflammation. Radiomics involves extracting quantitative features from medical images to create big data and identify novel imaging biomarkers.

METHODS

In a prospective case-control study, 60 patients with acute MI underwent CCTA within 48 h of admission, before invasive angiography. These subjects were matched to patients with stable CAD (n = 60) and controls with no CAD (n = 60) by age, sex, risk factors, medications, and CT tube voltage. PCAT was segmented around the proximal right coronary artery (RCA) in all patients and around culprit and nonculprit lesions in patients with MI. PCAT segmentations were analyzed using Radiomics Image Analysis software.

RESULTS

Of 1,103 calculated radiomic parameters, 20.3% differed significantly between MI patients and controls, and 16.5% differed between patients with MI and stable CAD (critical p < 0.0006); whereas none differed between patients with stable CAD and controls. On cluster analysis, the most significant radiomic parameters were texture or geometry based. At 6 months post-MI, there was no significant change in the PCAT radiomic profile around the proximal RCA or nonculprit lesions. Using machine learning (XGBoost), a model integrating clinical features (risk factors, serum lipids, high-sensitivity C-reactive protein), PCAT attenuation, and radiomic parameters provided superior discrimination of acute MI (area under the receiver operator characteristic curve [AUC]: 0.87) compared with a model with clinical features and PCAT attenuation (AUC: 0.77; p = 0.001) or clinical features alone (AUC: 0.76; p < 0.001).

CONCLUSIONS

Patients with acute MI have a distinct PCAT radiomic phenotype compared with patients with stable or no CAD. Using machine learning, a radiomics-based model outperforms a PCAT attenuation-based model in accurately identifying patients with MI.

Does the morbidity management and disability prevention (MMDP) clinic serve the filarial lymphedema (FLE) patients' preeminent expectation?

Advocacy and training on "Home care" for filarial lymphoedma (FLE) patients are provided through morbidity management and disability prevention (MMDP) clinic commonly known as filariasis clinic and clinical improvement is assessed by follow-up visits. While the physicians aim at reducing the recurrent ADL (coined as ADLA in 1997) episodes, the patients expect reduction in LE volume. The objective of the present study was to know whether the MMDP clinic serves the primary expectation of the FLE patients. LE patients who attended the clinic for at least four follow-up consultations and had LE volume measurements at three points of time during the one year period of observation were considered for analysis. Clinical assessment was done for LE grading and LE volume was measured by water displacement volumetry. Sixty-three patients who fulfilled the follow up criteria were included. It was observed that the median LE volume was 914ml (IQR 269 - 1935) at first visit of the observation period which reduced to 645ml (IQR 215- 1666) and 752ml (IQR 215 - 1720) at first and second follow-up visits respectively. Over all, in short span of one year, 21 of the 63 patients (33.3%) who visited MMDP clinic at least four times in a year were benefitted through the MMDP advocacy and the National filariasis control programme need to emphasise on the importance of follow up visits to FLE patients.

020 Increased risk of an abnormal cervical screening test in women with MS exposed to high-efficacy disease-modifying treatments

Introduction

Long-term exposure of women with Multiple sclerosis (MS, wwMS) to immunomodulatory or immunosuppressive treatments may increase the risk of cervical dysplasia. However, little is known about cervical dysplasia risk and Human Papillomavirus (HPV)-vaccine coverage in wwMS.

Methods

Adult wwMS were recruited from two tertiary MS clinics. To explore the association between MS treatments (DMTs) and abnormal cervical screening tests (CSTs), we linked individual data from MSBase, the Victorian Cervical Screening Registry, and National HPV vaccination program registry (NHPVPR).

Results

To date, we have recruited 208 wwMS of whom 102 had complete data (vaccination status, cervical screening tests, MSBase data) and no previous history of abnormal CST at MS onset for this interim analysis. The average age was 33.8 (18 to 59 yrs) and most (n=58, 88%) were unvaccinated. 19 wwMS (19%) had an abnormal CST after MS onset (incidence rate 20.6 cases/1000 person-years, 95% confidence interval 12.4–32.1) over average 9.0 years of follow-up. 57 wwMS were treated with lower-efficacy therapies (56%), 73 with a high-efficacy therapy (72%), and 44 were exposed to both. Eight abnormal CSTs were detected before starting high-efficacy therapy (rate 12.6, 95% CI (5.4–24.8)) and 11 were detected after starting high-efficacy therapy (rate 38.6, 95% CI (19.3–69.0), p=0.022.

Conclusion

We provide preliminary data that high efficacy DMTs may increase the risk of abnormal CSTs over time. A larger cohort and inclusion of additional cervical dysplasia risk factors are required to fully elucidate risk in wwMS.

Pattern of community compliance with spaced, single-dose, mass administrations of diethylcarbamazine or ivermectin, for the elimination of lymphatic filariasis from rural areas of southern India

Current programmes to eliminate lymphatic filariasis (LF) are largely based on annual mass administrations of single doses of antifilarial drugs. The level and pattern of compliance by the target population are important determinants of the success of such mass drug administrations (MDA). Community compliance was therefore investigated during a study in southern India of the effects, on Wuchereria bancrofti microfilaraemia and transmission, of spaced MDA based on diethylcarbamazine (DEC) or ivermectin (IVM). During six rounds of MDA, the frequency of compliance in the target populations, in the five study villages given DEC and the five given IVM, ranged from 55%-77%. Analysis of the relevant cohort data indicated that about 30% of the villagers had complied with treatment during all six rounds, but 3.5% of those in the DEC arm and 4.0% of those in the IVM arm had never complied with treatment. Most of the villagers (>90%) had received treatment at least once, however, and >60% had each received treatment in at least four of the six rounds. Overall, there was a significant negative correlation (r=-0.78; P=0.008) between the size of the village, in terms of the number of villagers, and the mean frequency of compliance over the six rounds of MDA. The pattern of community compliance was found to be 'semi-systematic', laying between random and systematic. In terms of the elimination of LF, a semi-systematic pattern of compliance is worse than random compliance but better than systematic. The relevance of the levels and patterns of compliance to LF control or elimination is discussed.

Detection of day blood filarial antigens by Og4C3 ELISA test using filter paper samples

BACKGROUND

The launching of the global filariasis elimination programme has necessitated the use of highly sensitive and specific diagnostic tests. The Og4C3 monoclonal antibody-based ELISA test has been found to be highly specific and sensitive for the diagnosis of filariasis using night blood samples. However, it requires a serum sample which poses problems of transport and storage. Collection of blood samples on filter paper the will greatly circumvent these problems. Therefore, we evaluated the utility of the Og4C3 assay on filter paper samples collected during daytime.

METHODS

Blood samples were collected from 63 microfilariae (mf) carriers during different time periods in a day on filter paper discs as well as venous blood for sera. The mf carriers and chronic (hydrocele n = 20; lymphoedema n = 120) and acute filariasis (adenolymphangitis n = 39) patients were from the endemic areas and the non-endemic normals were from Uthagamandalam district of Tamil Nadu, India. The filarial antigens in the samples were determined using the Og4C3 filarial antigen assay as per the manufacturer's instructions (JCU TrapBio, Australia). The sensitivity of the assay on sera and filter paper samples collected during night and also on filter paper samples collected during different time intervals of the day were compared with those of the membrane filtration technique, which was used as a gold standard.

RESULTS

The geometric mean titre of the sera samples collected during night was 11 units/ml for non-endemic normals and 601.2 units/ml for mf carriers. The specificity of the assay on sera samples collected during night was 100% and the sensitivity 96.8% and the positive and negative values were 100% and 95.2%, respectively. The antigen positivity of the filter paper samples collected during morning hours was 93.3% while it was 76.6% and 86.7% for afternoon and evening hours. A significant association was observed between antigenaemia levels and mf density in the blood samples collected during the night.

CONCLUSION

The samples collected on filter paper during the day can be used as an alternative to sera samples for detection of filarial antigens employing Og4C3 ELISA. Also, samples collected during morning hours yield a higher positivity. The assay when applied to serum samples will be useful especially when quantitative results are required.

The effect of six rounds of single dose mass treatment with diethylcarbamazine or ivermectin on Wuchereria bancrofti infection and its implications for lymphatic filariasis elimination

Annual mass treatment with single-dose diethylcarbamazine (DEC) or ivermectin (IVM) in combination with albendazole (ALB) for 4-6 years is the principal tool of lymphatic filariasis (LF) elimination strategy. This placebo-controlled study examined the potential of six rounds of mass treatment with DEC or IVM to eliminate Wuchereria bancrofti infection in humans in rural areas in south India. A percentage of 54-75 of the eligible population (> or =15 kg body weight) received treatment during different rounds of treatment - 27.4% in the DEC arm and 30.7% in the IVM arm received all six treatments, 4.8% and 5.6% received none, and the remainder received one to five treatments. After six cycles of treatment, the microfilaria (Mf) prevalence in treated communities dropped by 86% in the DEC arm (P < 0.01) (n = 5 villages) and by 72% in the IVM arm (P < 0.01) (n = 5 villages), compared with 37% in the placebo arm (P < 0.05) (n = 5 villages). The geometric mean intensity of Mf fell by 91% (t = 8.11, P < 0.05), 84% (t = 6.91, P < 0.05) and 46% (t = 2.98, P < 0.05) in the DEC, IVM and placebo arms, respectively. The proportion of high-count Mf (>50 Mf per 60 mm(3) of blood) carriers was reduced by 94% (P < 0.01) in the DEC arm and by 90% (P < 0.01) in the IVM arm. Among those who received all six treatments, 1.4% in the DEC arm and 2.4% in the IVM arm remained positive for Mf. Two of five villages in the DEC arm and one of five in the IVM arm showed zero Mf prevalence, but continued to have low levels of transmission of infection. The results also indicate that DEC is as effective as or slightly better than IVM against microfilaraemia. Results from this and other recent operational studies proved that single-dose treatment with antifilarials is very effective at community level, feasible, logistically easier and cheap and hence a highly appropriate strategy to control or eliminate LF. Higher treatment coverage than that observed in this study and a few more than six cycles of treatment and more effective treatment tools/strategies may be necessary to reduce microfilaraemia to zero level in all communities, which may lead to elimination of LF.

Quantifying mosquito biting patterns on humans by DNA fingerprinting of bloodmeals

A major debate in infectious disease epidemiology concerns the relative importance of exposure and host factors, such as sex and acquired immunity, in determining observed age patterns of parasitic infection in endemic communities. Nonhomogeneous contact between hosts and vectors is also expected to increase the reproductive rate, and hence transmission, of mosquito-borne infections. Resolution of these questions for human parasitic diseases has been frustrated by the lack of a quantitative tool for quantifying the exposure rate of people in communities. Here, we show that the polymerase chain reaction (PCR) technique for amplifying and fingerprinting human DNA from mosquito bloodmeals can address this problem for mosquito-borne diseases. Analysis of parallel human and mosquito (resting Culex quinquefasciatus) samples from the same households in an urban endemic focus for bancroftian filariasis in South India demonstrates that a 9-locus radioactive short-tandem repeat system is able to identify the source of human DNA within the bloodmeals of nearly 80% of mosquitoes. The results show that a person's exposure rate, and hence the age and sex patterns of exposure to bites in an endemic community, can be successfully quantified by this method. Out of 276 bloodmeal PCR fingerprints, we also found that on average, 27% of the mosquitoes caught resting within individual households had fed on people outside the household. Additionally, 13% of mosquitoes biting within households contained blood from at least 2 people, with the rate of multiple feeding depending on the density of humans in the household. These complex vector feeding behaviors may partly account for the discrepancies in estimates of the infection rates of mosquito-borne diseases calculated parasitologically and entomologically, and they underline the potential of this tool for investigating the transmission dynamics of infection.

Placebo-controlled community trial of four cycles of single-dose diethylcarbamazine or ivermectin against Wuchereria bancrofti infection and transmission in India

A double-blind placebo-controlled trial was carried out in 1994-98 to compare the effects of 4 cycles of single-dose diethylcarbamazine (DEC) or ivermectin on prevalence and geometric mean intensity (GMI) of microfilaraemia in the human population, infection rates in the vector population, and transmission intensity of Culex-transmitted Wuchereria bancrofti in rural areas in Tamil Nadu state, south India. Fifteen villages (population approximately 26,800) were included in the study: 5 villages each were randomly assigned to community-wide treatment with DEC or ivermectin or placebo. People over 14 kg bodyweight received DEC 6 mg/kg, ivermectin 400 micrograms/kg or a placebo, all identically packaged. After 2 cycles of treatment at a 6-month interval, the code was broken and the study continued as an open trial, with third and fourth cycles of treatment at a 12-month interval; 54-77% of eligible people (20,872) received treatment during the 4 cycles. Microfilaraemia prevalence and GMI fell by 48% and 65% with DEC and 60% and 80% with ivermectin respectively after 4 cycles of treatment. There was no change in the incidence of acute adenolymphangitis. Infection in resting mosquitoes fell significantly in all arms: 82%, 78% and 42% in the ivermectin, DEC and placebo arm, respectively. Landing mosquitoes also showed the same trend. The decline in infectivity was significant for resting (P < 0.05) and landing mosquitoes (P < 0.05) with ivermectin and DEC (P < 0.05), and for neither in the placebo group (P > 0.05). Transmission intensity was reduced by 68% with ivermectin and 63% with DEC. Transmission was apparently interrupted in 1 village with ivermectin, but infected resting mosquitoes were consistently found in this village. Single-dose community-level treatment with DEC or ivermectin is effective in reducing W. bancrofti infection in humans and mosquitoes, and may result in total interruption of transmission after several years of control. There is an immediate need to define the role of vector, parasite and community factors that influence the elimination of lymphatic filariasis, particularly the duration of treatment vis-à-vis efficacy of drugs, treatment compliance and efficiency of vectors.

Evaluation of the ICT whole blood antigen card test to detect infection due to nocturnally periodic Wuchereria bancrofti in South India

The commercially available ICT Card Test for bancroftian filariasis was evaluated for its sensitivity and specificity in detecting microfilaria carriers among 189 individuals each in filariasis-endemic and nonendemic areas in South India, and compared to both conventional night blood finger prick thick blood smear examination and venous blood membrane filtration. Though the specificity of the test was 100% in comparison to both, the sensitivity was 98.5% against the finger prick thick blood smear and 71.9 compared to the membrane filtration technique. Similarly, the positive predictive value was 100% against both techniques, but the negative predictive values were 99.5% against the finger prick thick blood smear and 88.3% compared to the membrane filtration technique. The test's lower sensitivity compared to the filtration technique requires further investigation.

Factors influencing response to lymphonodovenous shunt in filarial lymphoedema

BACKGROUND

Although several studies have been published on lymphonodovenous shunt, there are no objective data either on the outcome of lymphoedema or on various parameters likely to influence the results.

METHODS

A trial of lymphonodovenous shunt was carried out in 75 patients with unilateral filarial lymphoedema. The primary aim of the trial was to identify a cohort of responders as against non-responders and to correlate the outcome with various factors such as age, gender, duration and preoperative grade of lymphoedema, number of preoperative attacks of adenolymphangitis, operative impression of the lymph node, effect of venous reflex and type of nodovenous anastomoses. Change in oedema volume was measured objectively by water displacement method using the normal limb as a control.

RESULTS

There was no operative mortality. Predominant postoperative complications included wound haematoma (8.5%), wound infection (13.6%) and transient lymphorrhoea (13.6%). In the immediate postoperative period, a reduction of 25%-50% in the oedema volume was recorded in 46.7% of cases and of more than 50% in 17.3% cases. The difference in response with respect to the type of lymphonodovenous shunt was not statistically significant, although the end-to-side type of shunt showed marginally better results. The response was significantly higher in patients with preoperative oedema volume more than 2 L. There was a significant reduction in postoperative attacks of adenolymphangitis, irrespective of the reduction in oedema volume. Of the 75 patients, 22 showed regression of oedema volume to preoperative or higher levels in the postoperative phase. A majority (21/22) could be identified as non-responders within 3 months of surgery.

CONCLUSION

The best results of lymphonodovenous shunt were seen in patients with large-volume lymphoedema. The results are better when combined with early excisional surgery. Other factors did not significantly affect the outcome. Non-responders could be identified within 3 months after surgery. Even in patients who did not respond well, a significant decrease in the frequency of adenolymphangitis attacks was observed. Higher initial oedema volume and history of higher frequency (25-50 per year) of adenolymphangitis attacks can be considered as indicators for good response to lymphonodovenous shunt.

Omentoplasty in the management of filarial lymphoedema

A trial of omentoplasty was carried out on 20 patients with unilateral filarial lymphoedema to assess its role in the reduction of oedema volume after failed lymphonodo-venous shunt (LNVS) or as a primary procedure. Omentoplasty was done through a midline laparotomy. The omentum was mobilized from the colon, preserving both gastroepiploic vessels, and transferred to the thigh either through the lower end of the laparotomy incision or through a separate stab and placed subcutaneously in the upper third of the thigh. There was no operative mortality. Morbidity was mainly incisional hernia and superficial wound infection. Fourteen of 18 patients had more than 25% reduction in oedema volume during the immediate postoperative period, and 5 of the 18 had more than 50% reduction. However, there was a gradual loss of response with time. Age, gender, grade of lymphoedema, duration, and previous surgery did not influence the outcome. The incidence of incisional hernia could be reduced by transferring the omentum through the midline. There was a statistically significant reduction in postoperative adenolymphangitis attacks whether or not the oedema volume was reduced. In some patients the oedema was reduced sufficiently to permit subcutaneous excision of the lymphoedematous tissue. There appears to be a definite but limited role for omentoplasty in patients who have failed LNVS.

Tropical vaginal hydroceles: are they all filarial in origin?

Hydrocele of the tunica vaginalis testis has been conventionally used as an absolute indicator of filarial disease in most clinical surveys. The prevalence of filarial etiology in 100 consecutive hydroceles was studied using clinical, parasitological, histopathological and immunological parameters. Filarial etiology could be proved in 57% of hydrocele cases using major criteria: presence of microfilaria in hydrocele fluid, presence of chyle in hydrocele fluid, demonstration of adult worm in tunica, ratio of fluid antibody titer to serum antibody titer more than 2 and presence of filarial antigen in hydrocele fluid. The results of other tests in these 57 cases were used to define the minor criteria. In the other 43 cases, based on the minor criteria, 12 hydroceles could be classified as likely to be due to filariasis and the rest were probably non-filarial. Thus only 69% of hydroceles were definitely or probably filarial.

Limb circumference measurement for recording edema volume in patients with filarial lymphedema

To evaluate the impact of therapy and monitor the progression of filarial lymphedema, it is necessary to measure accurately the changes in limb edema volume. In this communication, we report the reliability of circumference measurements for recording volume changes. The measurements included the distal parts of limbs important for filarial lymphedema. In a series of 100 patients with unilateral lower limb lymphedema, both water displacement and circumference measurements were done. The results showed a significant correlation (r = 0.91; P = 0.0000) between the actual volume and that estimated by circumference measurement. Not only could volume of edema be calculated by circumference measurements, but the simple measurement of average circumference difference between the affected and normal limb accurately reflected the volume of actual edema.

Episodic adenolymphangitis and lymphoedema in patients with bancroftian filariasis

In order to explore the relationship between acute and chronic disease, age-specific data on the frequency and duration of episodic adenolymphangitis (ADL) in patients with 3 defined grades of lymphoedema in bancroftian filariasis were examined. The age distribution of grades I and II exhibited a convex age profile, but that of grade III showed a monotonic increase. The mean duration of oedema increased with its grade (grade I, 0.3 years; grade III, 9.9 years). The mean number of ADL episodes in the previous year for all cases was 4.2 and it increased with grade (grade I, 2.4 and grade III, 6.2). The mean duration of each ADL episode for all cases was 4.1 d and it was independent of grade and age. The mean period lost to ADL episodes in the previous year was 17.5 d; it increased from 9.4 d with grade I to 28.5 d with grade III. The results imply that there is a dynamic progression through the grades of lymphoedema and that the frequency of ADL episodes is positively associated with this progression. However, the study design could not separate cause from effect.