Estimating malaria transmission risk through surveillance of human-vector interactions in northern Ghana.

BACKGROUND: Vector bionomics are important aspects of vector-borne disease control programs. Mosquito-biting risks are affected by environmental, mosquito behavior and human factors, which are important for assessing exposure risk and intervention impacts. This study estimated malaria transmission risk based on vector-human interactions in northern Ghana, where indoor residual spraying (IRS) and insecticide-treated nets (ITNs) have been deployed. METHODS: Indoor and outdoor human biting rates (HBRs) were measured using monthly human landing catches (HLCs) from June 2017 to April 2019. Mosquitoes collected were identified to species level, and Anopheles gambiae sensu lato (An. gambiae s.l.) samples were examined for parity and infectivity. The HBRs were adjusted using mosquito parity and human behavioral observations. RESULTS: Anopheles gambiae was the main vector species in the IRS (81%) and control (83%) communities. Indoor and outdoor HBRs were similar in both the IRS intervention (10.6 vs. 11.3 bites per person per night [b/p/n]; z = -0.33, P = 0.745) and control communities (18.8 vs. 16.4 b/p/n; z = 1.57, P = 0.115). The mean proportion of parous An. gambiae s.l. was lower in IRS communities (44.6%) than in control communities (71.7%). After adjusting for human behavior observations and parity, the combined effect of IRS and ITN utilization (IRS: 37.8%; control: 57.3%) on reducing malaria transmission risk was 58% in IRS + ITN communities and 27% in control communities with ITNs alone (z = -4.07, P < 0.001). However, this also revealed that about 41% and 31% of outdoor adjusted bites in IRS and control communities respectively, occurred before bed time (10:00 pm). The mean directly measured annual entomologic inoculation rates (EIRs) during the study were 6.1 infective bites per person per year (ib/p/yr) for IRS communities and 16.3 ib/p/yr for control communities. After considering vector survival and observed human behavior, the estimated EIR for IRS communities was 1.8 ib/p/yr, which represents about a 70% overestimation of risk compared to the directly measured EIR; for control communities, it was 13.6 ib/p/yr (16% overestimation). CONCLUSION: Indoor residual spraying significantly impacted entomological indicators of malaria transmission. The results of this study indicate that vector bionomics alone do not provide an accurate assessment of malaria transmission exposure risk. By accounting for human behavior parameters, we found that high coverage of ITNs alone had less impact on malaria transmission indices than combining ITNs with IRS, likely due to observed low net use. Reinforcing effective communication for behavioral change in net use and IRS could further reduce malaria transmission.

Partial indoor residual spraying with pirimiphos-methyl as an effective and cost-saving measure for the control of Anopheles gambiae s.l. in northern Ghana.

The scale up of indoor residual spraying (IRS) and insecticide treated nets have contributed significantly to global reductions in malaria prevalence over the last two decades. However, widespread pyrethroid resistance has necessitated the use of new and more expensive insecticides for IRS. Partial IRS with pirimiphos-methyl in experimental huts and houses in a village-wide trial was evaluated against Anopheles gambiae s.l. in northern Ghana. Four different scenarios in which either only the top or bottom half of the walls of experimental huts were sprayed, with or without also spraying the ceiling were compared. Mortality of An. gambiae s.l. on partially sprayed walls was compared with the standard procedures in which all walls and ceiling surfaces are sprayed. A small-scale trial was then conducted to assess the effectiveness, feasibility, and cost of spraying only the upper walls and ceiling as compared to full IRS and no spraying in northern Ghana. Human landing catches were conducted to estimate entomological indices and determine the effectiveness of partial IRS. An established transmission dynamics model was parameterized by an analysis of the experimental hut data and used to predict the epidemiological impact and cost effectiveness of partial IRS for malaria control in northern Ghana. In the experimental huts, partial IRS of the top (IRR 0.89, p = 0.13) or bottom (IRR 0.90, p = 0.15) half of walls and the ceiling was not significantly less effective than full IRS in terms of mosquito mortality. In the village trial, the annual entomological inoculation rate was higher for the unsprayed control (217 infective bites/person/year (ib/p/yr)) compared with the fully and partially sprayed sites, with 28 and 38 ib/p/yr, respectively. The transmission model predicts that the efficacy of partial IRS against all-age prevalence of malaria after six months would be broadly equivalent to a full IRS campaign in which 40% reduction is expected relative to no spray campaign. At scale, partial IRS in northern Ghana would have resulted in a 33% cost savings ($496,426) that would enable spraying of 36,000 additional rooms. These findings suggest that partial IRS is an effective, feasible, and cost saving approach to IRS that could be adopted to sustain and expand implementation of this key malaria control intervention.

Familial adenomatous polyposis: a case study.

Familial adenomatous polyposis (FAP) is an inherited syndrome characterized by several adenomatous polyps of the gastrointestinal (GI) mucosa. If treatment is not provided, an average individual with classic FAP will develop colorectal carcinoma around the age of 40 years. The incidence rate of FAP in developing countries like Ghana is unknown compared to advanced countries. We present the first FAP case of a 22-year-old Ghanaian female who presented with massive lower GI bleeding and underwent surgical management after a thorough investigation. The initial assumption that colonic polyps are scarce in native Africans may be more than what is perceived. This highlights the need for the availability of endoscopic services in Ghana.

Acute Gastric Necrosis in a Teenager.

Gastric infarction is a rare condition often associated with high mortality due to a delay in diagnosis. The stomach which has a rich supply of blood is a rare site for such a condition. Gastric infarction has a long list of etiological factors. We report a case of a patient who was managed successfully following gastric infarction from gastric dilatation. An 18-year-old female student presented with a three-day history of abdominal pain associated with abdominal distension of two days. The abdomen was distended with generalized tenderness, rebound tenderness, and guarding. Bowel sounds were absent. Digital rectal examination was unremarkable, and a pregnancy test was negative. Biochemical tests were all normal. Intraoperatively, two litres of serosanguinous fluid was suctioned from the abdomen. About 300 mL of pus was suctioned from the pelvis. The gangrenous portion was resected, and repair was done in two layers using Conell and Lambert suture techniques. Acute gastric necrosis is a rare surgical condition that requires a high index of suspicion and prompts aggressive resuscitation and surgical intervention to obviate the high mortality rate associated with the condition.

Local anesthesia underutilized for inguinal hernia repair in northern Ghana.

INTRODUCTION: Inguinal hernia repair is a common procedure and a priority for public health efforts in Ghana. It is essential that inguinal hernia repair be performed in a safe, efficient manner to justify its widespread use. Local anesthesia has many favorable properties and has been shown to be superior, compared to regional or general anesthesia, in terms of pain control, safety profile, cost-effectiveness, resources required, and time to discharge. Local anesthesia is recommended for open repair of reducible hernias, provided clinician experience, by multiple international guidelines. Regional anesthesia is associated with myocardial infarction and other complications, and its use is discouraged by multiple guidelines, especially in older patients. This study aims to assess the current state of anesthesia for inguinal hernia repair in the northern and transitional zone of Ghana. In addition we will assess the perceptions of different types of anesthesia along with understanding of evidence-based guidelines among clinicians participating in inguinal hernia repair. METHODS: We performed a retrospective review of all inguinal hernia repairs for male patients, 18 and older, in over 90% of hospitals in northern Ghana. All 41 hospitals were visited and caselogs and patient charts were manually reviewed to extract data. Multivariate logistic regression was used to determine predictors of local anesthesia use. We designed a survey instrument to assess the perceptions of physicians and anesthetists regarding different types of anesthesia for inguinal hernia repair. The survey was designed by a Ghanaian surgeon, reviewed by all co-authors, and tested prior to implementation using a sample (n = 8) of clinicians having similar practices to those of the survey population. Of 70 clinicians, 66 responded, yielding a response rate of 94%. RESULTS: 8080 patients underwent hernia repair of which 37% were performed under local anesthesia, while the majority, 60%, were performed under regional anesthesia. Negative predictors of local anesthesia were emergent repair (OR = 0.258, p < 0.001), surgery performed at a teaching hospital (OR = 0.105, p < 0.001), and bilateral hernia repair (OR = 0.374, p < 0.001). 1,839 (22.8%) of IH repairs were done on patients age 65 or older and RA was most frequently used among the elderly population (57.8%), while local anesthesia was used 39.5% of the time. Sixty-six clinicians participated in the survey with the majority reporting that local anesthesia requires fewer staff, less equipment, has a shorter recovery, is more cost-effective, and might be safer for patients. However 66% were unfamiliar with or incorrectly perceived international guidelines. CONCLUSION: To our knowledge, this study is the largest assessment of anesthesia use for inguinal hernia repair in an LMIC. Although the selection of anesthetic technique should be guided by a patient's general health, the anatomy of the hernia, and clinician judgment, local anesthesia appears to be underutilized in northern Ghana. Survey responses demonstrate high rates of unfamiliarity or incorrectly perceived evidence-based guidelines. Future research should assess how education on the benefits and technique of local anesthesia administration may further increase rates for inguinal hernia repair, especially for older patients.

The use of mesh for inguinal hernia repair in northern Ghana.

BACKGROUND: Despite the recognition that inguinal hernia (IH) repair is cost-effective, repair rates in low- and middle-income countries remain low. Estimated use of mesh in low- and middle-income countries also remains low despite publications about low-cost, noncommercial mesh. The purpose of our study was to assess the current state of IH repair in the northern and transitional zone of Ghana. MATERIALS AND METHODS: A retrospective review of surgical case logs of IH repairs from 2013 to 2017 in 41 hospitals was performed. Multivariate logistic regression was used to determine predictors of mesh use. RESULTS: Eight thousand eighty male patients underwent IH repair. The range of IH repair in each region was 96 to 295 (overall 123) per 100,000 population. Most cases were performed at district hospitals (84%) and repaired nonurgently (93%) by nonsurgeon physicians (66%). Suture repair was most common (85%) although mesh was used in 15%. The strongest predictor of mesh use was when a surgeon performed surgery (odds ratio [OR] 3.13, P <0.001), followed by surgery being performed in a teaching hospital (OR 2.31, P <0.001). Repair at a regional hospital was a negative predictor of mesh use (OR 0.08, P <0.001) as was the use of general anesthesia (OR 0.40, P = 0.001). CONCLUSIONS: Most IH repairs are performed in district hospitals, by nonsurgeon physicians, and without mesh. Rates of repair and the use of mesh are higher than previous estimates in Ghana and Sub-Saharan Africa but not as high as high-income countries.