Prevalence and assemblage of Giardia duodenalis in a case-control study of children under 5 years from Jimma, Southwest Ethiopia

Giardia duodenalis is a common pathogenic intestinal protozoan parasite with high prevalence in developing countries, especially among children. The distribution of giardia assemblages among humans and their clinical relevance remains controversial. This study aimed to determine the prevalence and assemblage of Giardia among children under 5 years of age in Jimma, Southwest Ethiopia. Employing a case-control design, 606 children presenting with diarrhea at Jimma university medical center and Serbo Health Center were enrolled from December 2016 to July 2018 along with 617 matched controls without diarrhea. Giardia was detected and typed using real-time PCR. Univariate and multivariate regression analysis was performed. The total prevalence of Giardia was 41% (501/1223) and did not differ significantly between cases and controls (40% vs 42%). Prevalence increased by age, with the highest prevalence seen in children aged ≥ 25 months. Children without diarrhea with a history of diarrhea during the last month were more likely to be Giardia positive compared to children with no history diarrhea (OR 1.8 and 95%CI; 1.1-2.9). Regardless of current diarrhea symptoms, assemblage B predominated with 89%, followed by assemblage A (8%) and mixed infection assemblage A and B (3%). We report a high prevalence of Giardia by PCR detection in Jimma, Ethiopia, with assemblage B being predominant. There was a similar distribution of Giardia assemblages between children with and without diarrhea. Increasing age was a risk factor for Giardia infection. Community-based prevention and control strategies need to be employed to decrease the risk of giardia infection.

Oocyst Shedding Dynamics in Children with Cryptosporidiosis: a Prospective Clinical Case Series in Ethiopia

Knowledge on the duration of Cryptosporidium oocyst shedding, and how shedding may be affected by subtypes and clinical parameters, is limited. Reduced transmission may be a secondary benefit of cryptosporidiosis treatment in high-prevalence areas. We conducted a prospective clinical case series in children of <5 years presenting with diarrhea to a health center and a hospital in Ethiopia over an 18-month period. Stool samples were collected repeatedly from children diagnosed with cryptosporidiosis for up to 60 days. Samples were examined, and Cryptosporidium shedding was quantified, using auramine phenol, immunofluorescent antibody staining, and quantitative PCR (qPCR). In addition, species determination and subtyping were used to attempt to distinguish between new infections and ongoing shedding. Duration and quantity of shedding over time were estimated by time-to-event and quantitative models (sex- and age-adjusted). We also explored how diarrheal severity, acute malnutrition, and Cryptosporidium subtypes correlated with temporal shedding patterns. From 53 confirmed cryptosporidiosis cases, a median of 4 (range 1 to 5) follow-up stool samples were collected and tested for Cryptosporidium. The median duration of oocyst shedding was 31 days (95% confidence interval [CI], 26 to 36 days) after onset of diarrhea, with similar estimates from the quantitative models (31 days, 95% CI 27 to 37 days). Genotype shift occurred in 5 cases (9%). A 10-fold drop in quantity occurred per week for the first 4 weeks. Prolonged oocyst shedding is common in a pediatric clinical population with cryptosporidiosis. We suggest that future intervention trials should evaluate both clinical efficacy and total parasite shedding duration as trial endpoints. IMPORTANCE Cryptosporidiosis is an important cause of diarrhea, malnutrition, and deaths in young children in low-income countries. The infection spreads from person to person. After infection, prolonged release of the Cryptosporidium parasite in stool (shedding) may contribute to further spread of the disease. If diagnosis and treatment are made available, diarrhea will be treated and deaths will be reduced. An added benefit may be to reduce transmission to others. However, shedding duration and its characteristics in children is not well known. We therefore investigated the duration of shedding in a group of young children who sought health care for diarrhea in a hospital and health center in Ethiopia. The study followed 53 children with cryptosporidiosis for 2 months. We found that, on average, children released the parasite for 31 days after the diarrhea episode started. Point-of-care treatment of cryptosporidiosis may therefore reduce onward spread of the Cryptosporidium parasite within communities and households.

Performance and operational feasibility of two diagnostic tests for cryptosporidiosis in children (CRYPTO-POC): a clinical, prospective, diagnostic accuracy study

Background

Cryptosporidiosis is a common cause of diarrhoea in young children (aged younger than 24 months) in low-resource settings but is currently challenging to diagnose. Light-emitting diode fluorescence microscopy with auramine-phenol staining (LED-AP), recommended for tuberculosis testing, can also detect Cryptosporidium species. A lateral-flow test not requiring refrigerator storage (by contrast with most immunochromatographic lateral-flow assays) has also recently been developed for Cryptosporidium spp detection. We aimed to evaluate the diagnostic accuracy and operational feasibility of LED-AP and the lateral-flow test strip for cryptosporidiosis in children.

Methods

We did a prospective diagnostic accuracy study in two health-care facilities in Ethiopia, in a consecutive series of children younger than 5 years of age with diarrhoea (three or more loose stools within the previous 24 h) or dysentery (at least one loose stool with stains of blood within the previous 24 h). Stool samples were tested for Cryptosporidium spp by LED-AP and the lateral-flow test strip; accuracy of each test was estimated by independent and blind comparison with a composite reference standard comprising quantitative immunofluorescent antibody test (qIFAT), ELISA, and quantitative PCR (qPCR). Quantitative cutoff values for diarrhoea-associated infection were established in an embedded case-control substudy, with cases of cryptosporidiosis coming from the 15 districts in and around Jimma and the eight districts surrounding Serbo, and community controls without diarrhoea in the previous 48 h recruited by weekly frequency matching by geographical district of the household, age group, and enrolment week.

Findings

Stool samples from 912 children with diarrhoea or dysentery and 706 controls from the case-control substudy were tested between Dec 22, 2016, and July 6, 2018. Estimated reference-standard cutoff values for cryptosporidiosis positivity were 2·3 × 10⁵ DNA copies per g of wet stool for qPCR, and 725 oocysts per g for qIFAT. LED-AP had a sensitivity for cryptosporidiosis of 88% (95% CI 79–94; 66 of 75 samples) and a specificity of 99% (98–99; 717 of 726 samples); the lateral-flow test strip had a sensitivity of 89% (79–94; 63 of 71 samples) and a specificity of 99% (97–99; 626 of 635 samples).

Interpretation

LED-AP has high sensitivity and specificity for cryptosporidiosis and should be considered as a dual-use technology that can be easily integrated with existing laboratory infrastructures in low-resource settings. The lateral-flow test strip has similar sensitivity and specificity and provides an alternative that does not require microscopy, although purchase cost of the test strip is unknown as it is not yet available on the market.

Funding

Norwegian Research Council GLOBVAC fund, The Bill & Melinda Gates Foundation, Norwegian Society for Medical Microbiology, University of Bergen, and Vestfold Hospital Trust.

Critical evaluation of the appetite test for children with severe acute malnutrition

OBJECTIVES

The appetite test is used to risk stratify for children with severe acute malnutrition (SAM) in inpatient or outpatient care. The test is recommended in guidelines despite lack of evidence. We evaluated its ability to identify children at risk of a poor treatment outcome.

METHODS

We conducted an observational study of children diagnosed with SAM at three health facilities in Ethiopia. The appetite test was done independently, and the result did not affect decisions about hospitalisation and clinical care. Data were analysed using mixed linear and logistic regression models.

RESULTS

Appetite was tested in 298 (89%) of 334 children enrolled; 56 (19%) passed. Children failing the appetite test had a 6.6% higher weight gain per day (95% CI: 2.6, 10.8) adjusted for type of treatment, oedema, duration of follow-up and age than children passing the test. We found medical complications in 179 (54%) children. Medical complications were associated with blood markers of metabolic disturbance. Children with medical complications tended to have lower weight gain than those without complications (3.5%, 95% CI: -0.25, 7.0). Neither the appetite test nor medical complications were correlated with bacteraemia or treatment failure.

CONCLUSIONS

Our findings question the use of the appetite test to identify children who need inpatient care. An assessment of medical complications alone could be a useful risk indicator but needs to be evaluated in other settings.

Prolonged and persistent diarrhoea is not restricted to children with acute malnutrition: an observational study in Ethiopia

OBJECTIVES

To assess the prevalence of prolonged and persistent diarrhoea, to estimate their co-occurrence with acute malnutrition and association with demographic and clinical factors.

METHODS

Case-control study where cases were children under 5 years of age with diarrhoea and controls were children without diarrhoea, frequency-matched weekly by age and district of residency. Controls for cases 0-11 months were recruited from vaccination rooms, and controls for cases 12-59 months were recruited by house visits using random locations in the catchment area of the study sites. Data were analysed by mixed model logistic regression.

RESULTS

We enrolled 1134 cases and 946 controls. Among the cases, 967 (85%) had acute diarrhoea (AD), 129 (11%) had ProD and 36 (3.2%) had PD. More cases had acute malnutrition at enrolment (17% vs. 4%, P < 0.0001) and more were born prematurely (5.7% vs. 1.8%, P < 0.0001) than controls. About 75% of ProPD cases did not have acute malnutrition. Cases with AD and ProPD had different symptomatology, even beyond illness duration.

CONCLUSIONS

ProPD is common among children presenting with diarrhoea and is not confined to children with acute malnutrition. There is an urgent need for studies assessing causes of ProPD with and without acute malnutrition to develop treatment guidelines for these conditions.

Metronidazole-sensitive organisms in children with severe acute malnutrition: an evaluation of the indication for empiric metronidazole treatment

OBJECTIVES

Children with severe acute malnutrition (SAM) are treated with empiric amoxicillin or penicillin and gentamicin because of the high risk of severe infections. Experts have suggested, based on available evidence, adding metronidazole to cover anaerobic bacteraemia and diarrhoea caused by Giardia duodenalis or Clostridium difficile. The objective of this study was to assess the importance of these infections in children with SAM.

METHODS

Children from 6 months to 15 years with SAM were enrolled and followed clinically. Aerobic and, when patient weight permitted, anaerobic blood cultures were done using Bactec® system, and isolates identified with matrix-assisted laser desorption ionization-time of flight mass spectrometry. Stool samples were tested for C. difficile, G. duodenalis and Entamoeba histolytica by PCR.

RESULTS

A total of 334 children were enrolled and 174 out of 331 (53%) for which data on this was available had diarrhoea. Of 273 patients tested by blood culture, 11 had bacteraemia (4.0%, 95% CI 2.3-7.1%) but none with strict anaerobic bacteria (0/153, 95% CI 0-2.4%). There was no difference in the prevalence of C. difficile between children with (5/128, 4%) and without (7/87, 8%) diarrhoea (OR 0.47, 95% CI 0.14-1.53), and no difference in the prevalence of Giardia between these groups (78/138, 60% vs. 46/87, 53%; OR 1.34, 95% CI 0.77-2.32). Children with C. difficile had higher mortality than those without this infection (3/11, 27%, vs. 7/186, 4%; OR 43, 95% CI 3.9-483).

CONCLUSION

Our results do not provide support for empiric metronidazole to cover for anaerobic bacteraemia. Trials evaluating the effect of empiric treatment and its effect on G. duodenalis and C. difficile are warranted.