Impact of Pregnancy-Related Deaths on Female Life Expectancy in Zambia: Application of Life Table Techniques to Census Data

Immunization Coverage and Antibody Retention against Rabies in Domestic Dogs in Lusaka District, Zambia

Rabies remains endemic in Zambia. Despite conducting canine vaccinations in Lusaka district, the vaccination coverage and actual seropositivity in the dog population in Lusaka district are rarely evaluated. This study estimated the seropositivity-based immunization coverage in the owned dog population in Lusaka district using the expanded program on immunization cluster survey method. The time-series trend of neutralizing antibodies against rabies in vaccinated dogs was also evaluated. Of 366 dogs in 200 dog-owning households in Lusaka district, blood samples were collected successfully from 251 dogs. In the sampled dogs, 42.2% (106/251) had an antibody titer ≥0.5 IU/mL. When the 115 dogs whose blood was not collected were assumed to be seronegative, the minimum immunization coverage in Lusaka district's owned dog population was estimated at 29.0% (95% confidence interval: 22.4-35.5). It was also found that a single vaccination with certified vaccines is capable of inducing protective levels of antibodies. In contrast, higher antibody titers were observed in multiple-vaccinated dogs than in single-vaccinated dogs, coupled with the observation of a decline in antibody titer over time. These results suggest the importance of continuous booster immunization to maintain herd immunity and provide useful information to plan mass vaccination against rabies in Zambia.

Domestic dog demographics and estimates of canine vaccination coverage in a rural area of Zambia for the elimination of rabies

Background

An estimated 75% or more of the human rabies cases in Africa occur in rural settings, which underscores the importance of rabies control in these areas. Understanding dog demographics can help design strategies for rabies control and plan and conduct canine mass vaccination campaigns effectively in African countries.

Methodology/Principal findings

A cross-sectional survey was conducted to investigate domestic dog demographics in Kalambabakali, in the rural Mazabuka District of Zambia. The population of ownerless dogs and the total achievable vaccination coverage among the total dog population was estimated using the capture-recapture-based Bayesian model by conducting a canine mass vaccination campaign. This study revealed that 29% of the domestic dog population was under one year old, and 57.7% of those were under three months old and thus were not eligible for the canine rabies vaccination in Zambia. The population growth was estimated at 15% per annum based on the cross-sectional household survey. The population of ownerless dogs was estimated to be small, with an ownerless-to-owned-dog ratio of 0.01–0.06 in the target zones. The achieved overall vaccination coverage from the first mass vaccination was estimated 19.8–51.6%. This low coverage was principally attributed to the owners’ lack of information, unavailability, and dog-handling difficulties. The follow-up mass vaccination campaign achieved an overall coverage of 54.8–76.2%.

Conclusions/Significance

This paper indicates the potential for controlling canine rabies through mass vaccination in rural Zambia. Rabies education and responsible dog ownership are required to achieve high and sustainable vaccination coverage. Our findings also propose including puppies below three months old in the target population for rabies vaccination and emphasize that securing an annual enforcement of canine mass vaccination that reaches 70% coverage in the dog population is necessary to maintain protective herd immunity.

Because dogs are the main transmitter of rabies to humans, controlling rabies in dogs is essential for preventing rabies in humans. Canine vaccination is well-known as the most effective measure for controlling rabies in dogs. Understanding the demographics and dynamics of dog populations is important when designing efficient canine vaccination strategies. Furthermore, protective herd immunity in the total dog population should be attained through the vaccination of owned dogs since ownerless dogs are not usually covered in such campaigns. This study investigated domestic dog demographics and estimated the number of ownerless dogs to finally estimate the vaccination coverage among the overall dog population achievable through a mass vaccination campaign in a rural setting in Mazabuka District, Zambia. The target domestic dog population was young, and population growth was estimated at 15% annually based on the cross-sectional survey. The vaccination coverage attained by providing free canine mass vaccination campaigns was eventually estimated as 54.8–76.2% in the overall dog population, coupled with the estimate that the ownerless dog population was quite small. Our findings emphasize the necessity of conducting annual canine mass vaccinations, including puppies, that target 70% coverage in the dog population to maintain protective herd immunity.

Complications associated with adolescent childbearing in Sub-Saharan Africa: A systematic literature review and meta-analysis

Objective

To examine whether childbearing before age 18 in Sub-Saharan Africa is associated with increased risk of maternal and child complications through a systematic literature review and meta-analysis.

Methods

The literature on adolescent pregnancy and associated complications in Sub-Saharan Africa was reviewed. A systematic electronic database search in Medline and Embase identified relevant papers. Studies were eligible for inclusion if they had numeric data on maternal mortality, pre-eclampsia, eclampsia, preterm birth, low birth weight, small for gestational age, stillbirth, neonatal death or perinatal death. We included studies on adolescents aged 17 years or younger, and with a comparison group of adult women aged between 20 and 35 years. The quality of the articles was assessed. Meta-analyses were conducted when there were at least three included studies with minor clinical heterogeneity in population and outcome measures.

Results

Eighteen studies met our inclusion criteria. There were many studies from Sub-Saharan Africa with data on the age group 15–19 years old, but few studies had separate data on adolescents <18 years old. All included studies were of either moderate or low quality. Adolescents had an increased risk of low birth weight, pre-eclampsia/eclampsia, preterm birth and maternal and perinatal mortality. We found a lower, nonsignificant risk of stillbirth and for small for gestational age babies among the young mothers.

Conclusion

In this systematic review, the findings indicate that young maternal age is associated with some unfavorable outcomes in Sub-Saharan Africa. High quality observational studies that adjust for sociodemographic factors are lacking.

Cancer mortality trends in an industrial district of Shanghai, China, from 1974 to 2014, and projections to 2029

We aimed to characterize the trends and projections of cancer mortalities in Yangpu, an industry restructuring district of Shanghai, China. With high-quality data from the death registration system, the authors analyzed the trends in cancer mortalities during 1974-2014 and their relationship with pollution control and socioeconomic improvements. Cancer burden was projected into 2029. During 1974-2014, cancer death accounted for 28.80% of all-cause death. The 5 leading causes of cancer death were cancers of the lung & bronchus, stomach, liver, colon & rectum, and esophagus. Age-standardized mortality of all cancers was higher in men than in women (153.1/105vs. 88.8/105, p<0.001) and increased from 1974 to 1991 and decreased thereafter. The mortalities of cancers of the larynx, bladder, liver, nasopharynx, lung & bronchus, esophagus, lip oral & pharynx, stomach, kidney, and lymphoma were significantly higher in men than in women. Age-standardized mortalities of cancers of the esophagus, stomach, leukemia, female nasopharynx, female bladder, liver, and bone decreased especially after the 1990s, those of the colon & rectum, kidney, prostate, pancreas, breast, gallbladder, and ovary increased significantly. Lung cancer, breast cancer, colorectal cancer, and pancreas cancer in women and lung cancer, colorectal cancer, prostate cancer, and stomach cancer in men will be the leading causes of cancer death in 2025-2029. Cancer-caused life loss kept increasing since 2000. Conclusively, cancers associated with pollutions and infection decreased, especially after the 1990s, while those related to metabolic syndrome increased. These trends are related to closedown of polluted industries in the 1980s and lifestyle changes.