Otto Shill
April 2, 2011
Bio 1615
Article Summary Assignment
Selected Article: Assessment of Ultrasound Morbidity Indicators of Schistosomiasis in the
Context of Large-scale Programs Illustrated With Experiences From Malian Children.
In this article, a group of researchers detail a scientific study that they conducted to determine whether the World Health Organization (WHO) had suggested appropriate guidelines for using ultrasonography to diagnose two different forms of parasite-induced schistosomiasis. Ultrasonography is an effective diagnostic tool in third world countries because the technique is non-invasive and does not require hospitalization. The responsible parasites are Schistosoma haematobium and schistosoma mansoni. These parasitic infections are still very prevalent in developing countries and have symptoms that can have severe side effects if not properly treated. For example, schistosomiasis can result in hematuria (blood in urine), bloody diarrhea, hepatomegaly (swelling of the liver), hematemasis (bloody vomit), and other major pathologic effects on the bladder wall. Although researchers have not scientifically shown a direct connection, several other symptoms are suspected to be associated with this disease including anemia, chronic pain, and stunted growth, among others. Complications can be fatal. For example, complications from schistosoma mansoni infections lead to approximately 130,000 deaths per year in Sub-Saharan Africa and the disease can be easily transmitted. Schistosoma haematobium is typically transferred through fishing, market gardening, bodies of water such as ponds, streams, rivers and irrigation, while schistosoma mansoni is most often restricted to irrigation transmission (e.g. in rice cultivation).

In addition to the primary research goal of evaluating WHO standards, the researchers hoped to find indicators of parasitic schistosomiasis infection that could be detected with ultrasonography, and prepare for a large-scale treatment program of these infections. While many previous studies have covered a broad age spectrum, this study focused on more than
5,000 school-aged children in Mali who were randomly selected, typically in groups of about
180 from schools in affected areas. The researchers understood that it would be difficult to ensure that such a large number of children would participate in the entire course of study, so they designed the study to allow for a 40% drop out rate during the monitoring period. During two consecutive days the researchers collected urine samples from the children to screen for schistosoma haematobium. Researchers counted the number of parasitic eggs per 10 mL of urine to assess the intensity of schistosomiasis infection. Trained ultrasound professionals performed examinations according to WHO standards to screen for infections from both parasitic strains. In order to eliminate examination bias, these screenings were conducted blind so that the ultrasonographer was unaware of the child’s diagnosis. Children with schistosoma haematobium were examined first with a full bladder and second with an empty bladder.
Researchers were looking for shape changes of and lesions on the bladder wall and any dilation to the ureters or the renal pelvis. Ultrasonographers measured the infection in children infected with the schistosoma mansoni parasite by noting the size of the left liver lobe. Once the measurements had been taken, each infected child was provided with proper medical care including the WHO recommended doses of praziquantel to treat the schistosomiasis and albendazole to treat parasitic worms. The results were excellent as the childrens’ health improved and relatively few side effects were observed by the healthcare team.

Thorough statistical analysis included excluding the incomplete data from children who failed to complete the entire study. Sophisticated models were created to help physicians better understand and interpret ultrasonagrphic data. The researchers used sound statistical principles in developing their models and applied a 95% confidence interval to their calculations. Researchers found a strong association between schistosoma haematobium infected children and the positive global scores assigned to these children through ultrasound diagnostics. In addition, researchers concluded that the pathological effects of this parasitic infection were more pronounced in males than females. As expected, the schistosoma mansoni infections lead researchers to a statistically significant correlation between abnormal liver patterns and light, moderate, or heavy infections. Although, in this category, the WHO protocol was deemed to be overly cautious. In fact, it often leads to over-diagnosis of abnormal liver patterns. Researchers were able to develop patterns from their data that may be more appropriate to avoid over diagnosis, and they recommend adapting the WHO cutoff values to each localized region to minimize the overestimation of infection severity. When interpreted with caution and using local cutoff values, ultrasonography can prove valuable in a clinical diagnostic setting.
Even in light of the potential to overestimate the schistosoma mansoni infections, the researchers agree that the WHO protocol is a good public health tool and should be used, albeit with caution. Ultrasonography will definitely be very useful to clinicians diagnosing the effects of schistosoma haematobium and for defining the pathologic effect of urinary schistosomiasis.
Because ultrasonography is an inexpensive and non-invasive method of diagnosis, clinicians should be able to improve the quality of treatment available to infected individuals. This study

provided a significant contribution to allow progress in this area. Also, WHO recommended medicine doses were confirmed to be effective with minimal side effects. This study makes an important contribution to the body of existing research because the groups of children monitored were much larger than those involved in previous studies. In addition, this study confirms that the severity of schistosomiasis infections tends to cluster geographically.
Therefore, treating and diagnosing the affected population as a group can prove an important step to the recovery and well being of the group as a whole.
I believe the content of this research will help improve the current treatment patterns for these parasitic illnesses. As the principles are applied the symptoms of these infections can be more effectively diagnosed, and therefore treated. I was specifically impressed with the planning of the researchers that allowed them to translate their results into large-scale treatment plans to target community-wide treatment. Also, the authors were aware of, and recognized the limitations of their study (e.g. the exclusion of adults). Indeed, they responsibly called for others to fill in the gaps in their research. Hopefully, implementing the recommended changes to localize cutoff numbers for schistosoma mansoni diagnosis, along with implementing WHO dosing for treatment of these infections and their side effects, will provide a better life for the population of the third-world countries most afflicted.