Value of routine dengue diagnosis in endemic countries.

Dengue is one of the most common arthropod-borne viral diseases in humans and it is a leading cause of illness and death in the tropical and subtropical regions of the world. It is thought to account for 400 million cases annually among approximately 3.97 billion people at risk of infection in 128 endemic countries. Despite the global prevalence of the disease, the availability of a vaccine is limited in most countries in the endemic areas. Most endemic countries in South America, South East Asia and Africa serve as attractive touristic sites for people from non-endemic countries who become infected and export the virus to dengue-free regions. Dengue fever typically resembles malaria and in endemic countries most cases of dengue are treated as presumptive malaria. Consequently, routine dengue diagnosis among persons with fever will offer early treatment and reduce the burden of the disease. Also, routine testing among travellers from endemic countries will reduce importation and prevent the geographical expansion of dengue. In this essay, we seek to highlight the usefulness of routine dengue testing in endemic countries.

Point-of-care diagnosis and risk factors of infantile, rotavirus-associated diarrhoea in Calabar, Nigeria.

BACKGROUND: Rotaviruses are the primary cause of acute gastroenteritis in young children worldwide and a significant proportion of these infections occur in Africa. OBJECTIVES: In the present study, we determined the prevalence and risk factors of rotavirus infection among children younger than age 5 years with or without diarrhoea in Calabar, Nigeria, using a rapid point-of-care test. METHODS: Two hundred infants younger than age 5 years presenting with acute gastroenteritis and a control group of 200 infants without diarrhoea were tested for rotavirus. Each stool sample was homogenised in an extraction buffer and the supernatant added into the sample well of the Rida Quick rotavirus test cassette and allowed to run for 5 minutes at room temperature. When both the control band and test band were visible on the test cassette a positive result was recorded, whereas when only the control band was visible a negative results was recorded. RESULTS: Rotavirus was detected in 25 (12.5%) of children with diarrhoea and in no children without diarrhoea. Our results demonstrated that children who were exclusively breast-fed by their mothers were not infected with rotavirus and that 92% of the infants infected with rotavirus experienced vomiting. CONCLUSION: These data demonstrate that asymptomatic rotavirus infection is rare and that rotavirus is commonly detected in stool samples of children suffering from diarrhoea with concomitant vomiting. Use of point-of-care rotavirus tests will enhance early diagnosis of rotavirus-associated diarrhoea and reduce irrational use of antibiotics.

SELECTIVE INHIBITION OF HEPATITIS C VIRUS REPLICATION BY ALPHA-ZAM, A NIGELLA SATIVA SEED FORMULATION.

BACKGROUND: Hepatitis C virus (HCV) infection became curable because of the development of direct acting antivirals (DAAs). However, the high cost of DAAs has greatly impeded their potential impact on the treatment of HCV infection. As a result, hepatitis C will continue to cause substantial morbidity, and mortality among chronically infected individuals in low and middle income countries. Thus, urgent need exists for developing cheaper drugs available to hepatitis C patients in these countries. MATERIALS AND METHODS: Alpha-zam, an indigenous herbal formulation from Nigella sativa seed, was examined for its anti-HCV activity and cytotoxicity in genotype 1b HCV replicon cells. The antiviral activity was determined by luciferase expression and viral RNA synthesis, while the cytotoxicity was assessed by viable cell number and glyceraldehyde-3-phosphate dehydrogenase RNA synthesis in the replicon cells. RESULTS: Alpha-zam was found to be a selective inhibitor of HCV replication. The 50% effective dilution and 50% cytotoxic dilution of Alpha-zam were 761- and < 100-fold, respectively, in the subgenomic replicon cells LucNeo#2. Its selective inhibition of HCV was also confirmed by HCV RNA levels in LucNeo#2 and in the full-genome HCV replicon cells NNC#2 using real-time reverse transcriptase polymerase chain reaction. Furthermore, the anti-HCV activity of Alpha-zam was not due to the induction of interferon. CONCLUSION: Alpha-zam selectively inhibits HCV replication and therefore has potential for a novel antiviral agent against HCV infection.

Role of noroviruses as aetiological agents of diarrhoea in developing countries.

Diarrhoea is considered to be the second leading cause of death due to infections among children < 5 years of age worldwide that may be caused by bacteria, parasites, viruses and non-infectious agents. The major causative agents of diarrhoea in developing countries may vary from those in developed countries. Noroviruses are considered to be the most common cause of acute diarrhoea in both children and adults in industrialized countries. On the other hand, there is a lack of comprehensive epidemiological evidence from developing countries that norovirus is a major cause of diarrhoea. In these regions, asymptomatic norovirus infections are very common, and similar detection rates have been observed in patients with diarrhoea and asymptomatic persons. This review summarizes the current knowledge of norovirus infection in developing countries and seeks to position infections with noroviruses among those of other enteropathogens in terms of disease burden in these regions.

High dengue NS1 antigenemia in febrile patients in Ibadan, Nigeria.

We conducted a dengue seroprevalence survey among febrile patients positive or negative for malaria in Ibadan, Nigeria. Dengue IgG and NS1 seroprevalence of 73% and 35%, respectively, was observed, and 43% of those with malaria had acute dengue infection (NS1 determination). On the other hand, all participants with malaria were IgG dengue seropositive consistent with the endemicity of both arthropod-borne infections in the region. These data indicate that dengue is emerging as a major and neglected cause of fever in Nigeria.

Molecular characterization of diverse species enterovirus-B types from children with acute flaccid paralysis and asymptomatic children in Nigeria.

Non-polio enteroviruses (NPEVs) have often been identified in association with acute flaccid paralysis (AFP) in most polio surveillance studies worldwide. In a polio endemic country like Nigeria, there is need for distinction of AFP due to poliovirus and those potentially due to NPEVs. This study was undertaken to characterize the enterovirus (EV) types circulating in both children with and without AFP in Nigeria. Of fecal sample from 966 children with AFP, 96 (10%) were positive for NPEVs in RD cells, while 42 (5.5%) of 756 samples from non-AFP children was positive. Genotyping of all NPEV isolates was done by partial VP1 gene sequencing and phylogenetic analysis. EV-B was the predominant species detected (84%) and infection was common in children with AFP with CVB3, E6, and E11 constituting the predominant types detected. The CVB3 isolates cluster with Chinese CVB3 isolate recently detected in a newborn with AFP. There was also a remarkable clustering of isolates such as E6, E12, E13, E24, E30 and E33 to types previous detected in West Africa suggesting a probable circulation of these lineages in the region. Taken together, this study reveals a diverse species EV-B types in AFP cases and highlights the fact that other neurotropic EVs circulate in asymptomatic persons. Improved continuous surveillance of NPEV is warranted as in the likely attainment of polio eradication, other neurotropic EVs may emerge causing similar paralytic diseases.