Paediatric emergency medicine practice in Nigeria: a narrative review.

The practice of paediatric emergency medicine in Nigeria is still evolving, and laden with enormous challenges which contribute to adverse outcomes of childhood illnesses in emergency settings. Deaths from childhood illnesses presenting as emergencies contribute to overall child mortality rates in Nigeria. This narrative review discusses existing structures, organization, and practice of paediatric emergency in Nigeria. It highlights some of the challenges and suggests ways of surmounting them in order to reduce deaths in the children emergency units in Nigerian hospitals. Important aspects of this review include current capacity and need for capacity development, equipment needs for emergency care, quality of service in the context of inadequate healthcare funding and the need for improvement.

Burden of childhood and adolescence asthma in Nigeria: Disability adjusted life years.

BACKGROUND: A better representation of the burden of childhood asthma should rely on both morbidity and mortality and not only mortality. This will reduce the dearth of information on burden of childhood asthma, and enhance evidence-based decision-making. In this study, burden of childhood asthma was estimated, using disability-adjusted-life-years (DALYs), factoring in the disability weights for asthma, age at mortality and life expectancy. METHODS: The study was conducted at the University of Nigeria Teaching Hospital, Enugu. An Interviewer Administered Questionnaire was used to collect information from parents of children with asthma who presented to respiratory clinics regarding level of their asthma control (controlled, partially controlled and poorly controlled asthma), their age distributions, and gender. The prevalence of asthma, prevalence of associated disability, and case-fatality were obtained from previous publications. The DALYs were estimated by adding together the years lost to disability (YLDs) and years lost to life (YLLs) to asthma (DALYs = YLD + YLL). DALYs were dis-aggregated by age group and by whether their asthma were controlled, partially controlled and poorly controlled. RESULTS: A total of 66 children with asthma were studied. The proportion of the subjects with controlled, partially controlled and poorly controlled asthma were 26 (39.4%), 31 (47%), and 9 (13.6%) respectively. The subjects that had some form of asthma-related disability were 16 (24.3%). Childhood asthma caused 23.6-34.24 YLLs per 1000 population, 0.01-1.28 YLDs per 1000 population and 24.23-34.41 DALY per 1000 population. There was minimal difference in DALYs across the three clinical categories, but this was consistently higher among older children 12-17 years. The estimated national DALYs was 407820.2, reflecting about of 1.6% of the global all age (children and adults) DALYs of 24.8 million. CONCLUSION: The DALYs due to childhood asthma were high and did not vary much across the clinical categories, but increased with age. This imperatively necessitates the de-emphasis on just clinical responses as an indicator of the efficiency of childhood asthma control interventions but rather a holistic approach should be adopted considering the limitations the child suffers as a component of both life and environmental modification in a deliberate attempt to prevent attacks. The ability of the child to function optimally while on treatment should be considered in the treatment impact review.

Economic burden of childhood asthma in children attending a follow-up clinic in a resource-poor setting of Southeast Nigeria.

BACKGROUND: Beyond its chronicity, childhood asthma carries an economic burden for households. In this study we evaluated the cost of care of childhood asthma in a Nigerian household. METHODS: A cross-sectional hospital-based study. Relevant information was obtained through an interviewer-administered questionnaire. The cost of asthma treatment was estimated using direct medical costs and loss in productivity. Data analysis was done with SPSS version 22. A significant value of p < 0.05 was used. RESULTS: Sixty-six participants were enrolled, mean ±â€¯SD age (11.6 ±â€¯) the average direct cost was USD10.35. The cost of drug was USD5.8 and accounted for 56% of the direct cost. The loss in productivity was USD16.73. The mean cost per clinic visit was USD27.08, which was catastrophic in 12 (18.2%) households. The calculated annual cost of asthma treatment was USD162.49, with a cumulative national cost of USD 0.16 billion, which makes up 0.002% of the national GDP. CONCLUSION: The cost burden of asthma treatment may be low on the households but carries a huge national cost impact. We recommend the inclusion of asthma care in the Nigerian social health insurance as this may help reduce the financial burden due to asthma.

Pre-Transition Readiness in Adolescents and Young Adults with Four Chronic Medical Conditions in South East Nigeria - An African Perspective to Adolescent Transition.

INTRODUCTION: When a child reaches a certain age, he or she moves over to the adult physician. For this to maximally benefit the child, there has to be a process of equipping the child with skills required for taking on more responsibilities. Transitioning involves a process in which the adolescent with chronic illness is prepared ahead of time to enable them to eventually transfer to adult care with good outcomes. In high-income countries with well-organized health financing, the transitioning process begins as early as 12 years. In Africa, this process is not as organized and most hospitals would write a referral letter once the child turns 18 and transfer to adult clinic. In four of our chronic disease clinics (asthma, HIV, sickle cell anaemia and chronic kidney diseases) patients up to 24 years old are still attending the paediatric clinics. Understanding transition readiness among African adolescents remains a gap. Our findings will form a basis for informed practices for adolescent clinics in African countries. METHODS: This was a descriptive cross-sectional study of pre-transition readiness in adolescents and young adults with chronic illnesses attending four outpatient specialist clinics in a tertiary hospital in Enugu Nigeria. This was done using the validated STARx Questionnaire. Total scores were computed and scores nearer the upper limit of 90 were acceptable, while mean subdomain scores of 4 and above were considered as optimal level of transition readiness. Demographic and clinical data were also collected. Acceptability to move on to adult-oriented care was documented using binary response (yes/no). Cross tabulations were done, and likelihood ratios obtained for predictors of acceptability of transition. Significant value was set at p-value of ≤0.05. RESULTS: A total of 142 adolescents and young adults aged 12 to 24 years were studied. There were 38.0% (54), 24.6% (35), 22.5% (32) and 14.8% (21) from HIV, sickle cell anaemia, asthma and nephrology clinics, respectively. Their mean age was 15.6 years ± 2.4, and 48.6% (69) were male. The mean total transition readiness score was 56±14 and this was not nearer the higher spectrum of total scores obtainable. Highest mean scores (3.7) occurred in the knowledge subdomain while least mean score (2) was noted in the use of medication reminders. The males had highest scores in the knowledge subdomain while the females were better informed about medication adherence and were more inquisitive about their chronic illness. Only about 37% (53) of the adolescents and young adults welcomed the idea of moving on to adult-care clinics. Children who had less frequent emergency hospital visits and better treatment outcome accepted the idea of transfer to adult care. Irrespective of the age all participants had suboptimal subdomain scores. High scores did not influence the participants' choice to embrace transfer to adult care. CONCLUSION: There is suboptimal transition readiness irrespective of the age. The older age groups were less willing to transfer to adult care. Better disease knowledge and better communication skills did not positively influence acceptability of transfer to adult care.

A National Survey of Resources to Address Sepsis in Children in Tertiary Care Centers in Nigeria.

Background: Infections leading to sepsis are major contributors to mortality and morbidity in children world-wide. Determining the capacity of pediatric hospitals in Nigeria to manage sepsis establishes an important baseline for quality-improvement interventions and resource allocations. Objectives: To assess the availability and functionality of resources and manpower for early detection and prompt management of sepsis in children at tertiary pediatric centers in Nigeria. Methods: This was an online survey of tertiary pediatric hospitals in Nigeria using a modified survey tool designed by the World Federation of Pediatric Intensive and Critical Care Societies (WFPICCS). The survey addressed all aspects of pediatric sepsis identification, management, barriers and readiness. Results: While majority of the hospitals 97% (28/29) reported having adequate triage systems, only 60% (16/27) follow some form of guideline for sepsis management. There was no consensus national guideline for management of pediatric sepsis. Over 50% of the respondents identified deficit in parental education, poor access to healthcare services, failure to diagnose sepsis at referring institutions, lack of medical equipment and lack of a definitive protocol for managing pediatric sepsis, as significant barriers. Conclusions: Certain sepsis-related interventions were reportedly widespread, however, there is no standardized sepsis protocol, and majority of the hospitals do not have pediatric intensive care units (PICU). These findings could guide quality improvement measures at institutional level, and healthcare policy/spending at the national level.

Childhood diabetes: a myth or reality?- perception of the public from a low-income country: a cross-sectional study.

BACKGROUND: The diagnosis of Type 1 diabetes is commonly missed in most health facilities in Nigeria. Adequate knowledge of childhood diabetes is necessary for the recognition and possible intervention for the control of the disease. However, research to assess knowledge deficiencies and their relationship to attitude is lacking in most developing countries including Nigeria. This study intends to survey the beliefs and perceptions of caregivers of children towards diabetes in childhood. It also aims at determining the caregivers' depth of knowledge of diabetes in children, the relationship between knowledge and practices as well as the association between level of education and gender with practices and knowledge. The study outcome will help in the formulation of policy and education of the communities with regards to the preconceived myths and realities of childhood diabetes. METHODS: A descriptive study involving 500 respondents, population groups were selected by multi-staged sampling from different areas in Enugu metropolis, south-East of Nigeria. A validated structured interviewer-administered questionnaire was used. Ethical approval was obtained, and only consenting subjects were interviewed. Data was analyzed with Statistical Package for the Social Sciences (SPSS) version 20. RESULT: Almost all the respondents (99.8%) had heard of diabetes in adults. However, a lower proportion of respondents 43.2% knew about diabetes in childhood. Only 24.8% had good knowledge of the different aspects of diabetes. Although females were more knowledgeable about the effects of healthy life style modifications on diabetes, there was no gender predisposition in knowledge about diabetes in childhood. A positive association existed between knowledge and education [p < 0.001] concerning childhood diabetes. Irrespective of this association 82.6% of the respondents with good knowledge of the disease still had a poor attitude towards healthy life style practices. CONCLUSION: This study has shown that beliefs and perceptions of childhood diabetes among the adult caregivers in Enugu, south - East Nigeria is mostly erroneous and their knowledge deficient. Literacy did not improve both knowledge and attitude to healthy lifestyle practices.

Prevalence and determinants of airflow limitation in urban and rural children exposed to cooking fuels in South-East Nigeria.

Background Biofuels and other cooking fuels are used in households in low- and middle-income countries. Aim To investigate the impact of cooking fuels on lung function in children in urban and rural households in South-East Nigeria. Methods The multi-stage sampling method was used to enroll children exposed to cooking fuel in the communities. Lung function values FEV1, FVC and the FEV1/FVC ratio, were measured with ndd EasyOneR spirometer. Airflow limitation was determined with FEV1/FVC Z-score values at -1.64 as the lower limit of normal (LLN5). The Global Lung Function Initiative 2012 software was used to calculate the lung function indices. Results The median age (range) of the 912 children enrolled was 10.6 years (6-18). Altogether, 468 (51.6%) children lived in rural areas. Seven hundred and thirty-seven (80.7%) were directly exposed to cooking fuels (418/737, 56.5% in rural areas). Wood and kerosene were the dominant fuels in rural and urban households. The respective mean Z-scores of the exposed children in rural and urban were zFEV1 -0.62, FVC -0.21, FEV1/FVC -0.83 and zFEV1 -0.57, zFVC -0.14, FEV1/FVC -0.75. Few (5.2%, 38/737) of the children had airflow limitation. Most of them (60.5%, 25/38) lived in the rural community; the lowest FEV1/FVC Z-scores were those of exposed to a combination of fuels. Conclusion Exposure to cooking fuels affects lung function in children with airway limitation in a small proportion, Control measures are advocated to reduce the morbidity related to cooking fuels exposure.

Hematological Indices at Birth of Infants of HIV-Positive Mothers Participating in a Prevention of Mother-to-Child Transmission Program.

BACKGROUND: The mother-to-child transmission of HIV, which accounts for 90% of infections in children, has been reduced markedly through the use of antiretroviral drugs by pregnant women and their newborns. Changes to the World Health Organization guidelines support further extension of the prevention of mother-to-child transmission programs with increased risk of toxicity on the fetuses. AIM: To determine the hematological indices at birth of infants exposed in utero to maternal antiretroviral drugs. METHOD: A comparative analytical study of 126 neonates whose blood samples were analyzed to determine their hematological indices. RESULT: The hemoglobin, hematocrit, the total white blood cell (WBC) count and absolute neutrophil count (ANC) were significantly lower in infants of HIV-positive mothers. The total WBC and ANC were also significantly lower in the highly active antiretroviral therapy. HAART group and those exposed to maternal drugs for <1 year. CONCLUSION: There are significant changes in the hematological indices of infants of HIV-positive mothers at birth.

The performance evaluation of a urine malaria test (UMT) kit for the diagnosis of malaria in individuals with fever in south-east Nigeria: cross-sectional analytical study.

BACKGROUND: Accurate rapid diagnosis is one of the important steps in the effort to reduce morbidity and mortality of malaria. Blood-specific malaria rapid diagnostic tests (RDTs) are currently in use but other body fluid specific diagnostic test kits are being developed. The aim of the present study was to evaluate the performance characteristics of a one-step Urine Malaria Test™ (UMT) dipstick in detecting Plasmodium falciparum HRP2, a poly-histidine antigen in urine of febrile patients for malaria diagnosis. METHODS: This was an observational study in which a urine-based malaria test kit was used in malaria diagnosis in a normal field setting. Two hundred and three individuals who presented with fever (≥37.5°C) at seven outpatient clinics in Enugu State during periods of high and low transmission seasons in Southeastern Nigeria were enrolled. Matched samples of urine and blood of consecutively enrolled subjects were tested with UMT and blood smear microscopy. RESULTS: With the blood smear microscopy as standard, the disease prevalence was 41.2% and sensitivity for the UMT was 83.75% (CI: 73.81 to 91.95%, Kappa 0.665, p =0.001). The UMT had an LLD of 120 parasites/µl but the sensitivity at parasite density less than ≤200 parasites/µl was 50% and 89.71% at density ≥201 parasites/µl with specificity of 83.48%. The positive and negative predictive values were 77.91% and 88.07%, respectively. CONCLUSION: The UMT showed moderate level of sensitivity compared with blood smear microscopy. The test kit requires further improvement on its sensitivity in order to be deployable for field use in malaria endemic regions.

Immunogenicity and safety of the candidate RTS,S/AS01 vaccine in young Nigerian children: a randomized, double-blind, lot-to-lot consistency trial.

BACKGROUND: For regulatory approval, consistency in manufacturing of vaccine lots is expected to be demonstrated in confirmatory immunogenicity studies using two-sided equivalence trials. This randomized, double-blind study (NCT01323972) assessed consistency of three RTS,S/AS01 malaria vaccine batches formulated from commercial-scale purified antigen bulk lots in terms of anti-CS-responses induced. METHODS: Healthy children aged 5-17 months were randomized (1:1:1:1) to receive RTS,S/AS01 at 0-1-2 months from one of three commercial-scale purified antigen bulk lots (1600 litres-fermentation scale; commercial-scale lots), or a comparator vaccine batch made from pilot-scale purified antigen bulk lot (20 litres-fermentation scale; pilot-scale lot). The co-primary objectives were to first demonstrate consistency of antibody responses against circumsporozoite (CS) protein at one month post-dose 3 for the three commercial-scale lots and second demonstrate non-inferiority of anti-CS antibody responses at one month post-dose 3 for the commercial-scale lots compared to the pilot-scale lot. Safety and reactogenicity were evaluated as secondary endpoints. RESULTS: One month post-dose-3, anti-CS antibody geometric mean titres (GMT) for the 3 commercial scale lots were 319.6 EU/ml (95% confidence interval (CI): 268.9-379.8), 241.4 EU/ml (207.6-280.7), and 302.3 EU/ml (259.4-352.3). Consistency for the RTS,S/AS01 commercial-scale lots was demonstrated as the two-sided 95% CI of the anti-CS antibody GMT ratio between each pair of lots was within the range of 0.5-2.0. GMT of the pooled commercial-scale lots (285.8 EU/ml (260.7-313.3)) was non-inferior to the pilot-scale lot (271.7 EU/ml (228.5-323.1)). Each RTS,S/AS01 lot had an acceptable tolerability profile, with infrequent reports of grade 3 solicited symptoms. No safety signals were identified and no serious adverse events were considered related to vaccination. CONCLUSIONS: RTS,S/AS01 lots formulated from commercial-scale purified antigen bulk batches induced a consistent anti-CS antibody response, and the anti-CS GMT of pooled commercial-scale lots was non-inferior to that of a lot formulated from a pilot-scale antigen bulk batch.

Pattern of respiratory diseases in children presenting to the paediatric emergency unit of the University of Nigeria Teaching Hospital, Enugu: a case series report.

BACKGROUND: Respiratory diseases are one of the causes of childhood morbidity and mortality as well as hospitalization globally. The patterns of different respiratory illnesses in several parts of the world have been reported but there are few on the combined burden of the diseases. Determination of the burden of respiratory diseases as a group will help ascertain their collective impact on the health systems in order to develop intervention measures. METHODS: Data from case notes of children with respiratory diseases admitted to the University of Nigeria Teaching Hospital Enugu, Nigeria over a six year period were extracted. Age, gender, admission rates, types of respiratory illness, duration of admission, season of presentation and outcome were analysed. Descriptive and inferential (Chi square) statistics were used to describe the various disease types and ascertain association of the disease outcome, seasonal pattern with the types of diseases. RESULTS: Of the total of 8974 children admissions, 2214 (24.7%) were due to respiratory diseases. The mean age of all the children with respiratory diseases was 3.3 years (SD 3.9). Communicable diseases were the common cause of admission cases throughout the seasons, p < 0.001. The highest admission rates were for pneumonia, (34.0%), acute bronchial asthma, (27.7%) and rhinosinusitis (14.6%) p < 0.001. The frequency of respiratory disease decreases with age and children less than five years of age and of low socio-economic status were commonly affected, p=0.01. The median duration of hospital stay was two days [range 1 to 8 days], children less than five years old and those of low socio-economic status, spent more than four days (p=0.01 and p < 0.001 respectively). The all-cause mortality was 0.5% (11/2214) of which 81.8% (9/11) was due to pneumonia. CONCLUSIONS: Respiratory diseases constitute a significant burden of childhood illnesses in our centre. Efforts are required to reduce the impact as part of the steps towards the achievement of the Millennium Development Goals.

Epidemiology of rotavirus diarrhea among children younger than 5 years in Enugu, South East, Nigeria.

BACKGROUND: Severe rotavirus diarrhea in children is a major cause of morbidity globally and mortality in developing countries. It is estimated to be responsible for >453,000 deaths in children <5 years of age globally and 232,000 in the African region. The aim of the current study was to determine the prevalence of rotavirus gastroenteritis among hospitalized children <5 years of age in Enugu and to support awareness and advocacy efforts for the introduction of rotavirus vaccines in Nigeria. METHODS: World Health Organization-standardized case forms were used to collect data from eligible children with non-bloody diarrhea from October 2010 to September 2012. Data collected included socio-demographic and clinical information. Stool samples were obtained from recruited children and tested for rotavirus antigen using the Oxoid Prospect ELISA Kit (Basingstoke, United Kingdom). RESULTS: Of the 615 diarrhea stool samples collected, 344 (56%) were positive for human rotavirus. Of the 344 positive samples, 329 (96%) were children <2 years of age, while 247 (77%) were <1 year of age. Peak rotavirus season occurred during the cold dry months of December to April during which 95% of all cases occurred. CONCLUSIONS: This study found a relatively high incidence of severe rotavirus-associated diarrhea disease in Nigeria and infants were the most affected. It highlights the urgent need for introduction of rotavirus vaccine into the national immunization program and the need to adequately equip health facilities to enable them administer intravenous fluids to severe diarrhea patients to reduce morbidity and mortality.

A variant of pentalogy of Cantrell in a live birth.

Pentalogy of Cantrell which usually comprises of anomalies of the ectodermal and mesodermal tissues is a very rare congenital condition which in the extreme of cases is incompatible with life. In this report a variant of the condition in a live newborn baby who presented to the University of Nigeria Teaching Hospital with abnormalities of the heart, urinary bladder and sternum is discussed. The aim of the report is to create an awareness and high index of suspicion amongst health professionals.

Therapeutic efficacy and effect on gametocyte carriage of an artemisinin and a non-based combination treatment in children with uncomplicated P. falciparum malaria, living in an area with high-level chloroquine resistance.

Combination therapy with artemesinin or non-artemesinin-based antimalarials (ACTs or NACTs) are known to retard the development and progression of drug resistance in Plasmodium falciparum (P. falciparum). The optimal antimalarial combinations in Africa are yet unknown. We evaluate the therapeutic efficacy and effects on gametocyte carriage of Artemether-Lumefantrine (AL) and Amodiaquine-Sulfalene/Pyrimethamine (ASP) in children with P. falciparum malaria in an endemic area. One-hundred and thirty-nine children aged ≤ 10 years with uncomplicated P. falciparum malaria were enrolled. The primary end points were adequate clinical and parasitological response (ACPR), late parasitological failure(LPF), late clinical failure (LCF) and early treatment failure (ETF). Polymerase chain reaction (PCR)-corrected cure rates on days 14-42 and gametocyte carriage rates were determined. Fever clearance time was significantly shorter (P = 0.009) with ASP, but parasite clearance time was similar with both regimens. Day 28 cure rates were 91.4 and 89.9% (PCR-corrected) for AL and ASP respectively. Both regimens were well tolerated. Overall, gametocyte carriage before and following treatment were similar. Both combinations were found effective and comparable for treatment of acute, uncomplicated, P. falciparum malaria.

Malaria at parturition in Nigeria: current status and delivery outcome.

BACKGROUND: To evaluate the current status of malaria at parturition and its impact on delivery outcome in Nigeria. METHODS: A total of 2500 mother-neonate pairs were enrolled at 4 sites over a 12-month period. Maternal and placental blood smears for malaria parasitaemia and haematocrit were determined. RESULTS: Of the 2500 subjects enrolled, 625 were excluded from analysis because of breach in study protocol. The mean age of the remaining 1875 mothers was 29.0 +/- 5.1 years. The prevalence of parasitaemia was 17% and 14% in the peripheral blood and placenta of the parturient women, respectively. Peripheral blood parasitaemia was negatively associated with increasing parity (P < .0001). Maternal age <20 years was significantly associated with both peripheral blood and placental parasitaemia. After adjusting for covariates only age <20 years was associated with placental parasitaemia. Peripheral blood parasitaemia in the women was associated with anaemia (PCV < or =30%) lower mean hematocrit (P < .0001). lower mean birth weight (P < .001) and a higher proportion of low birth weight babies (LBW), (P = .025). CONCLUSION: In Nigeria, maternal age < 20 years was the most important predisposing factor to malaria at parturition. The main impacts on pregnancy outcome were a twofold increase in rate of maternal anaemia and higher prevalence of LBW.

Epidemiology of congenital malaria in Nigeria: a multi-centre study.

OBJECTIVE: To determine the burden of congenital malaria in newborns in Nigeria. METHODS: In a prospective multi-centre study, 1875 consecutive mother-baby pairs were enrolled over a continuous 12-month period. Blood smears were prepared from mothers, neonates, placental aspirates and cord blood within 4 h of delivery. Outcome variables were patent parasitaemia in the mother, placenta, cord and neonate in addition to maternal and neonatal haematocrit. RESULTS: Patent parasitaemia was detected in 95 neonates (5.1%). The occurrence varied between study centres, but was found year round in all sites. The mean parasite density among infected neonates was low (48 asexual forms per microl, range 8-200/microl). Maternal and placental parasitaemia were the most important risk factors for patent neonatal parasitaemia (P < 0.0001). Spontaneous clearance of parasitaemia occurred in 62.1% of neonates before day 2. 33.7% were symptomatic within 3 days of birth. CONCLUSION: Congenital malaria is often asymptomatic, clears spontaneously and may not warrant treatment. However, newborns with unexplained fever and refusal to feed in malaria endemic areas should be tested for malaria.

Epidemiology of Burkitt's lymphoma in Enugu, Nigeria.

Forty-four children between 3 and 14 years of age with Burkitt's lymphoma were studied at the University of Nigeria Teaching Hospital, Enugu, Nigeria from November 1991 to March 1995. Mean age at presentation was 7.6 years with a male:female ratio of 2.7:1. Eighty-six per cent of the patients lived in a rural area. Of the 23 (52%) from Enugu State, 16 were living in contiguous local government areas with ten clustered round the middle of the year. All the children were of the lowest socio-economic class, 75% of them being in class V. The incidence of Burkitt's lymphoma was higher during the dry season and the period of high malaria transmission (p < 0.05). Abdominal tumour was the commonest mode of presentation (32% of patients). Thirty-six patients were treated with cyclophosphamide, Oncovin, methotrexate and predinisolone (COMP), five received cyclophosphamide alone and three had cyclophosphamide, methotrexate and prednisolone (CMP). Multi-drug regimens achieved better results which were significantly unrelated to the number of cycles of therapy received. Overall, 48% had complete and 35% partial remission, 23% relapsed and 16 (36%) patients died. The epidemiological characteristics of Burkitt's lymphoma in this study were similar to those in other tropical regions.