Abdominal ultrasound in the diagnostic work-up of visceral leishmaniasis and for detection of complications of spleen aspiration

IntroductionAbdominal ultrasound (US) is increasingly used in the diagnostic work-up of infectious diseases, but studies on its diagnostic value in visceral leishmaniasis (VL) are lacking. US could help to identify complications of spleen aspiration (SA). We aimed to assess the diagnostic value of US and the evolution of findings after VL treatment; the incidence and degree of splenic injury; and the pain perceived during SA.Methodology/resultWe conducted a cross-sectional prospective study at the Leishmaniasis Research and Treatment Center, Gondar, Ethiopia between Oct 2017 and Dec 2018. We enrolled VL suspects undergoing tissue aspiration; US were conducted before and after SA, and at the end of VL treatment. Splenic injury was graded using the American association of surgery trauma injury scale (grade 1–4). The pain perceived during SA was graded using a visual analogue scale. Out of 392 VL suspects, 192 (49%) were confirmed VL cases. The median age was 25 years (IQR 21–30). Massive splenomegaly and hepatomegaly were the most common US findings. Splenic nodules were seen in 3.7% of the 190 VL cases and 1.5% of the 197 non-VL cases. Ascites was more common in VL (16.4%) than in non-VL cases (9.1%). The frequency of US abnormalities decreased with treatment. None of the US findings had sufficient sensitivity and specificity to justify its use as a diagnostic test. US detected splenic injury in four of the 318 patients who had post-SA US. All four patients remained clinically stable. Pain was perceived as moderate or severe in 51% of patients.ConclusionThe diagnostic value of abdominal US for VL was low but found useful to detect subclinical splenic injury. SA caries a risk of splenic injury and was perceived painful by most. Further research on less invasive diagnostic tools is needed.     

Diet overlap of non‐native common carp and native Nile tilapia: A potential cause for population reduction of Nile tilapia stock in Lake Ziway,Ethiopia

Lake Ziway harbours indigenous and exotic fish species including Nile tilapia (Oreochromis niloticus) and common carp (Cyprinus carpio). Nile tilapia was the dominant and preferred fish. However, its contribution to total catch has dramatically declined from 89.3% in 1994 to 27% in 2014 while the introduced common carp has increased from 0% before 2012 to 25% in 2014. Common carp potentially compete with Nile tilapia for available resources and could be a cause for the decline. Thus, the study explored the dietary overlap of the two species from April to August 2017. Schoener's overlap index (α) revealed significant dietary overlap between the two species (α = 0.84, between juveniles and α = 0.63, between adults). Juveniles fed mainly on animal origin (zooplankton and insects), while adult Nile tilapia have consumed plant origin (macrophyte and phytoplankton), and adult common carp fed on macrophytes and detritus. The presence of significant dietary overlap between the two species, particularly due to intense competition among juveniles, might cause the reduction of Nile tilapia stock because the native species has shown a competitive disadvantage for food in the presence of common carp. This study provides baseline information to researchers and decision makers working towards the sustainable resource utilisation of the system.     

Species composition,relative abundance and habitat association of small mammals along the altitudinal gradient of Jiren Mountain,Jimma, Ethiopia

To document the species composition, relative abundance and habitat association of small mammals, wet and dry season surveys were conducted along the altitudinal gradient of Jiren Mountain, Jimma area, Ethiopia. Sherman traps were used to capture small mammals from the six habitats: wetland, mixed plantation, open shrub, eucalyptus plantation, montane grassland and coffee plantation. The 393 trap nights, from the six habitat types, yielded 106 individual small mammals of tweleve species. The trapped rodents were Lophuromys flavopunctatus, Stenocephalemys albipes, Desmomys harringtoni, Mus mahomet, Lemniscomys barbarous, L. striatus, Tachyoryctes splendens, Mastomys natalensis and the insectivores Crocidura fumosa and C. turba. Two species of rodents Hystrix cristata and Helioscuirus gambianus were observed. Lophuromys flavopunctatus and S. albipes contributed 83.8% of the total capture. L. flavopunctatus, S. albipes and D. harringtoni were distributed in all habitats and gradients. T. splendens was captured from montane habitat, while the zebra mice were associated with the lower altitude habitats. Lophuromys flavopunctatus and M. natalensis extended their range deep into the coffee plantation habitats. Uncontrolled vegetation exploitation of the mountains for timber production and fire wood collection are the major threats. Conservation of the area to reduce the anthropogenic pressure is essential.     

Concentration of Lymph Node Aspirate Improves the Sensitivity of Acid Fast Smear Microscopy for the Diagnosis of Tuberculous Lymphadenitis in Jimma,Southwest Ethiopia

Background

Tuberculous lymphadenitis (TBLN) is the most common form of extrapulmonary tuberculosis. The cytomorphological features of lymph node smears have reduced specificity for the diagnosis of tuberculosis. The diagnosis of TBLN with direct smear microscopy lacks sensitivity due to the limited number of bacilli in lymph node aspirate. Therefore, we aimed to assess whether the concentration of lymph node aspirate improves the sensitivity of acid fast smear microscopy for the diagnosis of tuberculous lymphadenitis.

Methods

A cross-sectional comparative study was conducted on 200 patients clinically suspected for tuberculous lymphadenitis in Jimma, Ethiopia. Lymph node aspirate was collected. The first two drops were used for cytomorphological study and direct acid fast staining. The remaining aspirate was treated with N-acetyl-L-cysteine (NALC) and concentrated by centrifugation at 3000 g for 15 minutes. The sediment was used for acid fast staining and culture. Differentiation of M. tuberculosis complex (MTBC) from non-tuberculous mycobacteria (NTM) was done by para-nitrobenzoic acid susceptibility test.

Result

Complete data were available for 187 study subjects. 68% (127/187) were positive for M. tuberculosis on culture. Four isolates, 2.1% (4/187), were identified as NTM. The detection rate of direct smear microscopy was 25.1% and that of the concentration method 49.7%. Cytomorphologically, 79.7% of cases were classified as TBLN. The sensitivity of direct smear microscopy was 34.6%, for concentrated smear microscopy 66.1%, and for cytomorphology 89.8%. Two AFB positive cases on concentration method were non-tuberculosis mycobacteria (NTM). The concentration method yielded a positive result from seven cases diagnosed as suppurative abscess by cytology. Both for the direct and concentration methods the highest rate of AFB positivity was observed in smears showing caseous necrosis alone. Smear positivity rate decreased with the appearance of epithelioid cell aggregates.

Conclusion

The concentration of lymph node aspirates for acid fast smear microscopy had significantly higher sensitivity than direct microscopy.     

First combined resistance to Hessian fly and Sunn pest identified in synthetic hexaploid wheat

Hessian fly, Mayetiola destructor (Say), and Sunn pest, Eurygaster integriceps (Puton), are the two most damaging insect pests of wheat in North Africa, West and Central Asia. Host plant resistance is the most environmental friendly, cost-effective and practical means of controlling insect pests. Twenty synthetic hexaploid wheat lines selected as resistant to Syrian Sunn pest in 2010 were screened for resistance to Moroccan Hessian fly biotype in 2016. The Hessian fly screening was carried out in standard greenhouse flats using a randomized complete block design with three replications, with susceptible and resistant checks in every test flat. The results showed that three synthetic hexaploid wheat lines exhibited resistance to both Moroccan Hessian fly biotype and Syrian Sunn pest. This is the first record of combined resistance to these two pests in wheat. Mapping populations using these sources of resistance are being developed using double haploid techniques for subsequent genetic characterization and identification of linked molecular markers for marker assisted selection.     

Epilation for Minor Trachomatous Trichiasis: Four-Year Results of a Randomised Controlled Trial

BackgroundTrachomatous trichiasis (TT) needs to be managed to reduce the risk of vision loss. The long-term impact of epilation (a common traditional practice of repeated plucking of lashes touching the eye) in preventing visual impairment and corneal opacity from TT is unknown. We conducted a randomized controlled trial of epilation versus surgery for the management of minor TT (fewer than six lashes touching the eye) in Ethiopia. Here we report the four-year outcome and the effect on vision and corneal opacity.

Methodology/ Principal Findings

1300 individuals with minor TT were recruited and randomly assigned to quality trichiasis surgery or repeated epilation using high quality epilation forceps by a trained person with good near vision. Participants were examined six-monthly for two-years, and then at four-years after randomisation. At two-years all epilation arm participants were offered free surgery. At four-years 1151 (88.5%) were re-examined: 572 (88%) and 579 (89%) from epilation and surgery arms, respectively. At that time, 21.1% of the surgery arm participants had recurrent TT; 189/572 (33%) of the epilation arm had received surgery, while 383 (67%) declined surgery and had continued epilating (“epilation-only”). Among the epilation-only group, 207 (54.1%) fully controlled their TT, 166 (43.3%) had minor TT and 10 (2.6%) had major TT (>5 lashes). There were no differences between participants in the epilation-only, epilation-to-surgery and surgery arm participants in changes in visual acuity and corneal opacity between baseline and four-years.

Conclusions/ Significance

Most minor TT participants randomised to the epilation arm continued epilating and controlled their TT. Change in vision and corneal opacity was comparable between surgery and epilation-only participants. This suggests that good quality epilation with regular follow-up is a reasonable second-line alternative to surgery for minor TT for individuals who either decline surgery or do not have immediate access to surgical treatment.     

QTL mapping identifies a major locus for resistance in wheat to Sunn pest (<Emphasis Type="Italic">Eurygaster</Emphasis><Emphasis Type="Italic">integriceps</Emphasis>) feeding at the vegetative growth stage

Key message

This research provides the first report of a major locus controlling wheat resistance to Sunn pest. It developed and validated SNP markers that will be useful for marker-assisted selection.

Abstract

Sunn pest (Eurygaster integriceps Puton) is the most destructive insect pest of bread wheat and durum wheat in West and Central Asia and East Europe. Breeding for resistance at the vegetative stage of growth is vital in reducing the damage caused by overwintered adult populations that feed on shoot and leaves of seedlings, and in reducing the next generation of pest populations (nymphs and adults), which can cause damage to grain quality by feeding on spikes. In the present study, two doubled haploid (DH) populations involving resistant landraces from Afghanistan were genotyped with the 90k SNP iSelect assay and candidate gene-based KASP markers. The DH lines and parents were phenotyped for resistance to Sunn pest feeding, using artificial infestation cages at Terbol station, in Lebanon, over three years. Quantitative trait locus (QTL) analysis identified a single major locus on chromosome 4BS in the two populations, with the resistance allele derived from the landrace accessions, IG139431 and IG139883. The QTL explained a maximum of 42 % of the phenotypic variation in the Cham6 × IG139431 and 56 % in the Cham6 × IG139883 populations. SNP markers closest to the QTL showed high similarity to rice genes that putatively encode proteins for defense response to herbivory and wounding. The markers were validated in a large, unrelated population of parental wheat genotypes. All wheat lines carrying the ‘C–G’ haplotype at the identified SNPs were resistant, suggesting that selection based on a haplotype of favourable alleles would be effective in predicting resistance status of unknown genotypes.

     

Effects of inhibiting CoQ10 biosynthesis with 4-nitrobenzoate in human fibroblasts

Coenzyme Q(10) (CoQ(10)) is a potent lipophilic antioxidant in cell membranes and a carrier of electrons in the mitochondrial respiratory chain. We previously characterized the effects of varying severities of CoQ(10) deficiency on ROS production and mitochondrial bioenergetics in cells harboring genetic defects of CoQ(10) biosynthesis. We observed a unimodal distribution of ROS production with CoQ(10) deficiency: cells with <20% of CoQ(10) and 50-70% of CoQ(10) did not generate excess ROS while cells with 30-45% of CoQ(10) showed increased ROS production and lipid peroxidation. Because our previous studies were limited to a small number of mutant cell lines with heterogeneous molecular defects, here, we treated 5 control and 2 mildly CoQ(10) deficient fibroblasts with varying doses of 4-nitrobenzoate (4-NB), an analog of 4-hydroxybenzoate (4-HB) and inhibitor of 4-para-hydroxybenzoate:polyprenyl transferase (COQ2) to induce a range of CoQ(10) deficiencies. Our results support the concept that the degree of CoQ(10) deficiency in cells dictates the extent of ATP synthesis defects and ROS production and that 40-50% residual CoQ(10) produces maximal oxidative stress and cell death.