Comparative evaluation of various diagnostic techniques for detection of Cryptosporidium infection from the faecal samples of diarrhoeic bovine calves

BACKGROUND

Cryptosporidium, an opportunistic, zoonotic, apicomplexan parasite, is one of the most common causes of diarrhea in neonatal bovine calves around the globe. Bovine calves act as a major source of infection by excreting huge numbers of highly resistant oocysts in faeces, which can survive for a long time in extreme environmental conditions. As low as ten oocysts can cause disease and mortality, leading to the requirement of an early and accurate diagnosis for proper and favorable prognosis, management, and control.

AIMS

The current study was conducted with the objective to evaluate various diagnostic techniques (acid fast staining, negative staining, fluorescent, ELISA, PCR, nested PCR, and qPCR) for the detection of Cryptosporidium in the faecal samples of diarrheic bovine calves.

METHODS

Two hundred diarrheic faecal samples from bovine calves were collected and subjected to these techniques for Cryptosporidium diagnosis. Results of these were evaluated for diagnostic comparison.

RESULTS

Out of 200 faecal samples evaluated, 24% (48/200) were detected positive for Cryptosporidium using a combination of two techniques as gold standard criteria. Cohen's kappa value indicated moderate to almost perfect agreement (0.616 to 0.986) among all the techniques used in the present study. Leishman staining showed the lowest sensitivity (54.17%), while nested PCR and qPCR showed the highest sensitivity (97.92%). Diagnostic specificity of all these tests ranged from 98.68 to 100%.

CONCLUSION

Auramine stain was used for the first time in the bovine calves in India for the detection and diagnostic comparison of Cryptosporidium. It showed strong agreement with the molecular as well as classical diagnostic techniques, and can be used for primary screening for better diagnosis.

Comparative study for intermediate crystal size of NaI(Tl) scintillation detector

The distinctive features of a well-known NaI(Tl) scintillation detector, by virtue of its crystal size, are experimentally investigated by observing changes in parameters such as intrinsic efficiency (ε_i), photo-peak efficiency (ε_p), resolution, and response function to incident gamma photon energy. This study provides a better understanding for the choice of crystal size of the scintillation detector in Compton scattering experiments. The response function of the NaI(Tl) detector is in the form of an inverse matrix focusing on the retort of the crystal when gamma photons are incident upon it. The response function of the NaI(Tl) detector depends upon the distance between the source and the detector, composition of the material for the crystal itself, photo-fraction, solid angle, incident gamma energy, and geometry of the experimental setup. The factors responsible for broadening of full energy and backscattered peaks are discussed for present investigations. The observed results indicate that the resolution of the detector varies with the incident energy of gamma radiation, and it also depends upon the size of the crystal of the detector. Statistical fluctuations related with the scintillation mechanism are found to be responsible for broadening of instrumental line width (photo-peak). The signal-to-noise ratio and photo-fraction for different crystal sizes of the scintillation detector corrected for efficiency of the detector are also discussed.

Exploring animal rabies endemicity to inform control programmes in Punjab, India

Previous studies estimate that one-third of the annual global burden of rabies (~20,000 cases) occurs in India. Elimination of canine rabies is essential to reduce this burden. Surveillance of animal cases can assess both the risk to humans and the efficacy of control strategies. The objective of this study was to describe the spatial and temporal occurrence of reported confirmed cases of rabies in animals in Punjab, India, from 2004 to 2014. We analysed passive surveillance data on 556 samples submitted from 2004 to 2014 to GADVASU, Ludhiana, Punjab, India. Regression and time series analyses were conducted to understand seasonal and long-term variation of cases and identify cross-correlation of monthly cases between species. Spatio-temporal analyses assessed spatial autocorrelation of date of reporting, mean geographic centres of disease occurrence and clustering of cases using Kulldorff's space-time permutation statistic. The annual number of submissions and proportion of confirmed cases were consistent throughout 2004-2014. Most submissions (320; 57.6%) were confirmed rabies cases, including dogs (40.6%), buffalo (29.7%) and cattle (23.1%). Regression analysis of monthly cases in dogs showed seasonal variation with significant increases in cases in March and August. Monthly case numbers in buffalo decreased over time. Long-term temporal trend was not detected in dog and cattle cases. Time-series models identified significant cross-correlation between dog and buffalo cases, suggesting that buffalo cases were spillover events from dogs. Significant spatio-temporal variation or clusters of cases were not detected. These results indicate that rabies cases in animals-and therefore, the potential for exposure to humans-were temporally and spatially stable during 2004-2014 in Punjab, India. The endemic nature of rabies transmission in this region demands a coordinated, sustained control programme. This study provides baseline information for assessing the efficacy of rabies control measures and developing seasonally targeted dog vaccination and rabies awareness strategies.

Non-destructive study of wood using the Compton scattering technique

A simple nondestructive method is presented in this study to characterize woods having different densities, thus estimating the size and depth of inhomogeneities in given wood samples using the Compton scattering technique (CST). This technique uses a collimated beam of 662-keV energy from ¹³⁷Cs radioactive source, and the scattered flux is detected by an NaI(Tl) detector. To characterize different wood samples on the basis of their densities, both scattering and transmission experiments were performed. The presence of inhomogeneities such as knots in wood was simulated by drilling cylindrical voids of diameter 9mm in the samples and then filling them with a high-density material (aluminum). Furthermore, different sizes of inhomogeneities (Al cylinders) were filled in the wood samples to estimate the depth and size of the inhomogeneity using the CST. A higher linear correlation (R² ~ 0.96) was found between the scattered intensity and the density of different woods using the CST than that using the transmission (R² ~ 0.83) method by measuring the density range. An increase of 24.6% in the average scattered intensity was observed at the location where the knot was present, and it was found that an inhomogeneity of the order of ~4mm or more could be detected by the CST.

Morphometric and scanning electron microscopy based identification of Ancylostoma caninum parasites in dog

Ancylostoma caninum, a blood feeding nematode parasite (Family: Ancylostomatidae, Superfamily: Ancylostomatoidea) can cause anaemia, dark reddish-brown to black haemorrhagic diarrhoea, dehydration, wasting and deaths due to heavy blood loss. Adult hook worm parasites recovered from the intestine of a stray dog at the time of necropsy were identified as A. caninum based on morphological characters and morphometric observations involving scanning electron microscopy (SEM). Different developmental stages of hookworm eggs viz. 8 cell stage, morula, gastrula and vermiform were observed during the culture process of faecal sample. High quality SEM photographs showed teeth of dimensions 52.5, 42.3 and 23.5 μm on one side and 55.4, 43.8 and 21.0 μm on the other side along with the presence of characteristic transverse cuticular striations on body surface of A. caninum parasites.

Validation of Romanowsky staining as a novel screening test for the detection of faecal cryptosporidial oocysts

Cryptosporidiosis is an emerging waterborne protozoan disease and one of the major causes of neonatal diarrhea in humans and animals. But the disease remains under diagnosed due to lack of availability of special stains in majority of laboratories at primary health centers. Therefore, it requires a rapid screening test for routine diagnosis in conventional laboratory set up. In this pursuit, the present study was planned. During this study, fecal samples from 100 representative animals randomly selected from 17 out breaks of bovine calf diarrhea, were stained with modified Ziehl Neelsen staining (mZN) and Leishman's stain to demonstrate cryptosporidial oocysts and for routine fecal examination, respectively. By mZN staining, 25 cases confirmed the presence of cryptosporidial oocysts. However, examination of Leishman's stained fecal smears revealed round hollow unstained bodies resembling cryptosporidia in 20 cases. Therefore, a comparative morphometric analysis was made between the two techniques to determine their relative efficacy in demonstrating cryptosporidia in the feces of affected animals. The analyses showed that the Leishman's stain can be effective in making a presumptive diagnosis of cryptosporidiosis with a little experience. Confirmation of cryptosporidiosis was done by histopathological examination of intestinal sections of calves died during these out breaks. The findings appear to have great clinical value for routine laboratory screening of fecal samples for cryptosporidiosis as conventional Romanowsky stains are readily available and used for multipurpose examination in most of the laboratories at grass root level. Perusal of literature proved this to be the first attempt at easy diagnostics for cryptosporidiosis.

Incoherent scattering of gamma photons for non-destructive tomographic inspection of pipeline

A scanner system, operating in a non-destructive and non-invasive way, is presented for pipeline to determine its location in land soil, wall thickness, type of liquid flowing and crack/blockage position. The present experiment simulates a real case where pipe corrosion (wall thinning) under insulation can be known from the study of incoherent scattering of 662 keV gamma photons. The incoherent scattered intensity, obtained by unfolding (deconvolution) the experimental pulse-height distribution of NaI(Tl) scintillation detector with the help of inverse response matrix, provides the desired information. The method is quite sensitive for small change (approximately 1 mm) in the thickness of pipe wall, locating a defect of 1mm width under insulation and a small change (approximately 0.1 gm cm(-3)) in the density of liquid flowing through pipe.

Response function of NaI(Tl) detectors and multiple backscattering of gamma rays in aluminium

The response function, converting the observed pulse-height distribution of a NaI(Tl) detector to a true photon spectrum, is obtained experimentally with the help of an inverse matrix approach. The energy of gamma-ray photons continuously decreases as the number of scatterings increases in a sample having finite dimensions when one deals with the depth of the sample. The present experiments are undertaken to study the effect of target thickness on intensity distribution of gamma photons multiply backscattered from an aluminium target. A NaI(Tl) gamma-ray detector detects the photons backscattered from the aluminium target. The subtraction of analytically estimated singly scattered distribution from the observed intensity distribution (originating from interactions of primary gamma-ray photons with the target) results in multiply backscattered events. We observe that for each incident gamma photon energy, the number of multiply backscattered photons increases with increase in target thickness and then saturates at a particular target thickness called the saturation thickness (depth). Saturation thickness for multiply backscattering of gamma photons is found to decrease with increase in energy of incident gamma-ray photons.

Rabies in South Asia: epidemiological investigations and clinical perspective

A five year study (1995-1999) was conducted in Northern India to investigate epidemiological aspects of rabies in domestic animals. For this purpose, brain tissue samples were collected from rabies suspect animals including 231 dogs, 79 buffaloes, 46 cattle and 28 wild species. Out of the 384 rabies suspected cases, 56% were positive for rabies by fluorescent antibody test (FAT), the mouse inoculation test (MIT) and histopathological techniques. Variations in clinical signs of rabies were recorded for individual animals with significant differences observed between dogs and bovines with respect to hypersalivation, paralysis, recognition of owners and aggression. Likewise, differences in the clinical course of disease between cows and buffaloes regarding hypersalivation and micturition were observed. Rabies incidence was highest among adult male dogs and indicated a seasonal pattern with more rabies cases during certain months of the year (January to April, and August to November). Its impact on cow/buffalo rabies is discussed. Accumulated history records revealed that 78% of owned rabid dogs were not prophylactically vaccinated against rabies.

Effect of detector collimator and sample thickness on 0.662MeV multiply Compton-scattered gamma rays

The simultaneous effect of detector collimator and sample thickness on 0.662 MeV multiply Compton-scattered gamma photons was studied experimentally. An intense collimated beam, obtained from 6-Ci (137)Cs source, is allowed to impinge on cylindrical aluminium samples of varying diameter and the scattered photons are detected by a 51 mm x 51 mm NaI(Tl) scintillation detector placed at 90 degrees to the incident beam. The full energy peak corresponding to singly scattered events is reconstructed analytically. The thickness at which the multiply scattered events saturate is determined for different detector collimators. The parameters like signal-to-noise ratio and multiply scatter fraction (MSF) have also been deduced and support the work carried out by Shengli et al. [2000. EGS4 simulation of Compton scattering for nondestructive testing. KEK proceedings 200-20, Tsukuba, Japan, pp. 216-223] and Barnea et al. [1995. A study of multiple scattering background in Compton scatter imaging. NDT & E International 28, 155-162] based upon Monte Carlo calculations.

Beneficial effects of 'lamivudine pulse' therapy in HBeAg-positive patients with normal ALT*

Currently no therapy is given to patients with chronic hepatitis B virus (HBV) infection who are HBeAg positive with normal alanine aminotransferase (ALT) levels. Steroid priming has been shown to enhance T-helper-1 (Th-1) cell response. Lamivudine may restore immunologic competence against HBV by causing a sudden decline in the level of the virus. We examined the efficacy of lamivudine pulse therapy on the seroconversion from HBeAg to anti-HBe. This was a prospective single-blinded trial including 27 patients with chronic hepatitis B, HBeAg positive with ALT < or =1.5 times upper limit of normal (ULN). Lamivudine was administered initially for 4 weeks, then stopped for 2 weeks and later restarted and continued till 3 months after seroconversion or completion of 2 years of therapy. Twenty-six patients completed the study. Lamivudine withdrawal led to a rise in ALT levels above the ULN in 11 (42.3%) patients at 6 weeks; seven of them (63.6%) lost HBeAg compared with only two of the 15 patients (13.3%), in whom ALT levels did not rise (P = 0.011). As one patient showed a relapse, a total of eight (31%) patients responded to lamivudine pulse therapy over a mean period of 17.3 +/- 4.5 months. Responders had a higher serum albumin (P < 0.05), a lower fibrosis score (P < 0.05), and a relatively high baseline serum ALT levels (P = 0.024) than the nonresponders. YMDD mutations developed in three patients and none responded. No patient developed hepatic decompensation. Hence lamivudine pulse therapy has potential in converting HBeAg-positive, 'not-treat-worthy' (ALT < 1.5 ULN) patients to treat-worthy (ALT > 1.5 ULN) in 42%, with sustained HBeAg and HBV DNA loss in 31% patients. The effects are possibly because of a combination of antiviral and immunomodulating activities of lamivudine.

Efficacy of endoscopic wire guided biliary brushing in the evaluation of biliary strictures

Endoscopic brush cytology is a valuable technique for the evaluation of biliary strictures. The sensitivity of this technique varies from 30% to 83%, however, it can have specificity of 100%. We retrospectively evaluated the usefulness of wire-guided biliary brush cytology in biliary strictures in our hospital over a 3 years period from 1997 to 2000. Brushings from 58 biliary strictures were obtained during endoscopic retrograde cholangiography. They were compared with histological proof obtained by surgical biopsy or percutaneous fine-needle aspiration cytology and/or clinical findings. These were reported as benign or malignant. Eleven patients were excluded due to incomplete data. Eighteen patients had benign brushings. Fourteen of the 29 patients in whom histological confirmation of malignancy brushings was obtained were also reported as malignant. The sensitivity of endoscopic brushings was 48.2%, specificity 100% and diagnostic accuracy 55.2%. No major complications were seen in our study group.

Considerations for esthetic facial surgery in the African-American patient

Due to the diverse ethnic nature of most communities, the perception of beauty is not homogeneous. Beauty is a perception of good balance, symmetry, harmony, and features that are pleasing to the eye. It is not possible to quantitate beauty. Many attempts have been made to standardize what is and is not beautiful by establishing the ethnic norms. Surgeons commonly attempt to achieve these ideal norms, but they may not necessarily be considered beautiful by the individual patient. Therefore, it is imperative for the surgeon to completely understand the patients' goals for surgery, which may not fit the ideal norms published in studies for that specific ethnic community. It also has become essential for patients to be made aware of the limitations of surgery, especially if their goals are unrealistic, to avert future distress and medicolegal problems. Thus, what is "normal" is not necessarily beautiful, and perhaps it would be better to strive for what is considered beautiful to the individual patient, rather than normal. Within the African-American population, the concept of what is beautiful can be extremely diverse. The number of African Americans who seek cosmetic or esthetic facial surgery is limited. As the number of esthetic procedures performed in the African-American population increases, however, the more educated this population will become regarding these procedures, and the more comfortable the surgeon will become regarding his or her own sense of "African-American beauty" and specific esthetic facial considerations for this population. It should be mentioned that as the number of African-American surgeons increases, their influence within the African-American population regarding the availability of esthetic procedures will also be felt.

Paraganglionoma of extrahepatic biliary tract causing obstructive jaundice

We report a young woman with paraganglionoma arising from the extrahepatic bile duct presenting with acute obstructive jaundice. The patient underwent excision of the gall bladder and extrahepatic bile duct with the tumor, and Roux-en-Y hepaticojejunostomy. She is asymptomatic 9 months later, with normal biochemical investigations and imaging.

Haematological and biochemical studies in broiler chicks fed ochratoxin and inoculated with inclusion body hepatitis virus, singly and in concurrence

Day-old broiler chicks, which had been shown to be negative for maternal antibodies against inclusion body hepatitis (IBH) virus and for viral antigen in cloacal swabs, were divided into four groups of 20 chicks each. One group was fed ochratoxin-A at 0.5 ppm from 3 to 38 days of age, another group was inoculated with 1 ml of IBH virus containing 10(6.5) EID50 per 0.2 ml. A third group was given both ochratoxin-A and infected with IBH virus. The fourth group served as the control. Anaemia was observed in all three treated groups but the changes were more pronounced in the combined group. The biochemical changes also suggested a cumulative damaging effect by ochratoxin-A and IBH virus.

Giant cavernous hemangiomas of liver mimicking metastasis

Most hepatic hemangiomas are small and symptomless. These are now being increasingly diagnosed with the greater use of scanning procedures. Hemangiomas can occasionally grow to a large size and become manifest to the patient and the clinician. Giant hemangiomas can produce symptoms including awareness of abdominal mass, pain due to thrombosis, and very rarely, rupture. Though ultrasound is known to be quite suggestive of the diagnosis, large hemangiomas may be mistaken for liver metastases due to their enormous size and variegated picture on the scanning procedure. Dynamic CT scan and at times MRI may be required for confirmation of the diagnosis. Needle biopsy is contraindicated if the diagnosis is suspected.

Pathological studies in broiler chicks fed aflatoxin or ochratoxin and inoculated with inclusion body hepatitis virus singly and in concurrence

Day-old broiler chicks found negative for maternal antibodies against inclusion body hepatitis (IBH) virus by agar gel precipitation test and viral antigen in cloacal swabs by dot enzyme immunoassay were divided into 6 groups of 20 chicks each. Group A was fed aflatoxin B1 at 1.25 ppm from 3 to 38 days of age; group O was fed ochratoxin A at 0.5 ppm from 3 to 38 days of age; group V was inoculated with 1 ml of IBH virus of titre log10 6.5 EID50 per 0.2 ml. Groups AV and OV were given aflatoxin B1 and ochratoxin A, respectively, and also infected with the virus. Group C served as control. There was mild enlargement and paleness of the liver up to 18 days post inoculation in group V; there were no lesions in group A; and there was gradual enlargement of the kidneys from 10 days post feeding of mycotoxin onwards in group O. In the combined groups AV and OV the gross lesions were slightly more severe. In group V, varying degrees of degenerative histopathological changes, congestion and haemorrhages were seen particularly in the liver, followed by the kidneys, bursa, spleen, myocardium and lungs, along with intranuclear inclusion bodies in the hepatocytes, mostly in the early stages of infection. Similar microscopic changes, but without inclusion bodies, were seen in groups A and O and the changes were pronounced in the later stages. In group O, the kidney lesions were more pronounced than the liver lesions. In the concurrently infected groups, AV and OV, the changes were similar but slightly more marked than in the corresponding individual groups. Inclusion bodies in hepatocytes were more frequent, more prominent and appeared earlier in the concurrent groups.

Sustained release methadone salts and methadone-naloxone mixtures. Part 2: In vitro studies of methadone release

Various tablet formulations, using two methadone salts namely methadone-alpha-naphthalenesulfonate and methadone-o-benzoylbenzoate and a number of methadone-naloxone combinations were prepared. The quantities of methadone released from these tablets in simulated gastric and intestinal fluids were examined using spectrophoto-metric studies. All formulations followed a typical release pattern, indicating a high degree of consistency of the formulations.

Methadone salts. Part 1: preparation and identification

The preparation of two methadone salts, namely: methadone-alpha-naphthalenesulfonate and methadone-o-benzoyl-benzoate is described. The prepared compounds were confirmed by t.l.c. and IR spectroscopic studies.