Clinical and Epidemiological Information Required for Lyme Disease Surveillance in a Low-Incidence State, California 2011–2017. Brummitt et al. 2024. Vector-Borne and Zoonotic Diseases [ahead of print]. https://doi.org/10.1089/vbz.2024.0043

Abstract [shortened]: Background: Between January 1, 2011, and December 31, 2017, over 12,000 case reports of Lyme disease (LD) were submitted to the California Reportable Disease Information Exchange for further investigation. The number of case reports has tripled compared to previous years, emphasizing the need for efficient estimation and classification methods. We evaluated whether estimation procedures can be implemented in a low-incidence state such as California to correctly classify a case of LD.

Objective: This study identified whether a minimum number of variables was sufficient to reliably classify LD cases in California and potentially reduce workload. Methods: To determine the relative value of diagnostic information, we compared five candidate logistic regression models that were used to classify cases based on information that varied in its degree of difficulty for collection. Results: Our results showed that automatically reported data were not sufficient, additional information such as a patient’s clinical presentation and travel history were necessary to improve the sensitivity of the models. Conclusion: This study demonstrated that both clinical and travel information were required to accurately classify a case of LD in California.

Note: These results were critical to interpret data from a passive case surveillance system to identify areas of high risk endemic transmission.

A scoping review to determine if adverse human health effects are associated with use of organophosphates for mosquito control. Tai, Z. et al. 2024. Journal of Medical Entomology, 2024, 1–11.

https://doi.org/10.1093/jme/tjae130

Abstract [shortened]. Organophosphate insecticides are widely used for adult mosquito control. Although proven effective in reducing mosquito populations and limiting arbovirus transmission, public concern exists regarding potential human health effects associated with organophosphate exposure. The aim of this scoping review was to describe any reported human health conditions associated with organophosphates during their use for adult mosquito control in the United States and Canada. Original peer-reviewed articles published in English language journals from 1 January 2000 to 22 May 2024 identified 6,154 screened articles. Following an independent review, 10 studies were identified that described human health conditions associated with organophosphate exposure during adult mosquito control applications. Of the 10 included studies, only two articles were published within the last 11 years (2013 to 22 May 2024). The included studies could not determine causality between exposure to adulticides and development of illness or adverse impacts. The available and limited evidence indicates that organophosphates can be used safely to control nuisance mosquitoes or mosquitoes that transmit arboviruses. Continued research regarding the human health effects associated with organophosphate applications for adult mosquito control could help evaluate the basis of the public’s concerns and inform public health decision-making.

Malson,M. [downloaded: 30 Nov 24] https://www.bovinevetonline.com/news/education/new-world-screwworm-latest-update-usda-aphis

[Abbreviated]
On Nov. 25, USDA’s Animal and Plant Health Inspection Service (APHIS) held a meeting to discuss the U.S. response to the news of a single case of New World Screwworm (NWS) found in a cow in Chiapas, Mexico. U.S. and Mexican officials are working closely together, but the border has been temporarily closed to live cattle imports.

“Our priority is to ensure there is no risk to our domestic industry, followed by the goal of reopening the border as soon as possible,” says Dr. Michael Watson, administrator of USDA’s APHIS.

In September, work had already begun on protocols in the event NWS was found in Mexico. Those protocols have been reviewed with Mexico for their understanding and will be made public once finalized.

Points of Protocol

Dr. Burke Healey, senior leader for policy and operations for APHIS, shared protocol will likely include pre-export inspections by Mexican veterinarians overseen by SENASICA, the equivalent to APHIS, before allowing cattle imports to resume. The inspections will make sure:

– appropriate logs accompany animals coming into and leaving the facility cattle are treated with ivermectin

– there’s a seven-day quarantine period

Upon passing inspection, cattle will again be inspected by U.S. officials, along with additional inspections for tuberculosis and ticks. The cattle will be dipped, and then presented to cross the border. Healey says federal inspection sites will focus on ports in Chihuahua and Sonora. “Those five ports are on the Mexican side, so those inspections and all of that protocol are taking place in Mexico and not on U.S. soil,” he explains.

Mexico has not completed its investigation, but acknowledges the infested cow might have been imported from Guatemala. While the timeline for reopening trade is tentatively estimated to be at least three weeks, it quite possibly could extend into January as Mexico typically closes ports for two weeks during Christmas and New Year’s, Healey says.

The U.S. imports 1 million to 1.1 million cattle from Mexico annually. All Mexican cattle are required to have a Mexican origin ear tag and documentation of the herd of origin, TB test of that herd of origin and a TB test of the specific animals being presented for export. These requirements will remain in place.

Sterile flies from a Panama facility will be sent to Mexico to help control the spread of NWS further south and into Central America. Capacity from that facility is around 95 million per week. Mexico is also looking at retrofitting fruit fly plants to produce about 60 million sterile files a week.

Note: The continued release of millions of sterile males from a mass production facility in Panama supported by the USDA historically established a barrier for these flies at the Darian Gap. However, recently the flies have bridged this barrier and re-established infestations in Guatemala, perhaps in association with uncontrolled migrant convoys. This has triggered the increase in sterile fly production and releases, but has not eliminated this population. Historically, the screwworm was eradicated in Guatemala and Belize in 1994, El Salvador in 1995, and Honduras in 1996.

Louis, S. et. al. 2024. Emerg Inf Dis 30(12). DOI: https://doi.org/10.3201/eid3012.240655.

Abstract
In a US survey of infectious disease specialists, 61 respondents reported seeing >1 Bartonella quintana [‘trench fever’] infection during 2014–2024. Diagnostic challenges included limited healthcare provider awareness, inadequate testing, and inconsistent healthcare access among affected populations. Early recognition of B. quintana infections is needed to improve outcomes among affected populations. Note: This letter extends previous findings in California by CDPH reporting the isolation of this pathogen from body lice collected from the homeless and serves as a reminder of the importance of providing basic health care and sanitation for all members of society.

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Date: Tue 19 Nov 2024 16:20 ET Source: CNN Spanish [in Spanish, trans. Mod.TY, edited] https://cnnespanol.cnn.com/2024/11/19/alerta-puerto-rico-aumento-dengue-orix

The Puerto Rico Department of Health (DSPR) reported on Sunday [17 Nov 2024] that the number of confirmed positive cases of dengue on the island so far in 2024 is 4798, a significant increase of more than triple compared to 2023, when 1242 were recorded.

In a press release, the DSPR indicated that “to date, 9 deaths have been confirmed and an additional one is under investigation.”

“The Department of Health has implemented all the necessary tools to deal with this situation. It is fundamental that communities commit to eliminating mosquito breeding sites, using repellent and protecting themselves from bites. Without citizen participation, it is impossible to contain this epidemic,” said Dr. Carlos Mellado, Secretary of Health, in the letter.

The Puerto Rico Department of Health explained that mosquito repellents have been given to people at mass events and training has been conducted for field health professionals, in addition to updating the guide for ordering dengue diagnostic tests.

Among the municipalities with the highest incidence are San Juan with 995 cases, followed by Carolina with 293 and Rincón with 240. The most affected age groups are people from 40 to 59 years old (936 cases), adolescents from 15 to 19 years old (737), and children from 10 to 14 years old (683), the statement said.

Last March [2024], the department had issued a public health emergency declaration for dengue because the reported cases were at historic levels. At that time, 549 cases of dengue had been recorded.

Note: An advanced warning for those planning to attend the 2025 AMCA meeting in San Juan. All the hurricanes and rain this winter may extend these case numbers by March. Bring repellent!

Cardenas, R. et al. 2024. Med Vet Entomol. 2024;1–14. DOI: 10.1111/mve.12776 Abstract [Shiortened]. Ground water tanks are known to be preferred Aedes aegypti oviposition places providing opportunities for adult and larvae control. A dual-effect insecticidal coating (IC) (alphacypermethrin/ pyriproxyfen) with a slow-release mechanism represents a promising option. Bioassays were designed to determine the mortality and sterilizing effects on gravid mosquitoes exposed to IC. The inhibition of emergence was evaluated in eggs, larvae and pupae exposed in different containers. For the water safety assessment con-centrations of active ingredients were determined by reverse phase high performance liquid chromatography (RP-HPLC) and the health risk was calculated. The IC applied to the interior walls of water-holding containers showed efficacy against Ae. aegypti in terms of high gravid-female mortality (81% at 24 h, p < 0.01), sterilizing effect (inhibition of oviposition by 63%, p < 0.01) and emergence inhibition (100% in eggs, L3 and L4; 97% in pupae). Emergence inhibition was recorded up to 12 months and adult mortality >80%up to 6 months. The use of water stored in treated containers, either for washing or drinking, is not expected to pose a health risk to users. IC applied to domestic water containers has dual and complementary action that reduces Ae. aegypti densities (immature and adult stages).

Note: This approach could be useful in problem underground storm water systems as well as electrical vaults in California.

HLC Dutra, et al. PLoS Negl Trop Dis 18(9): e0012482. https://doi.org/10.1371/journal.pntd.0012482

Abstract Background: We sought to understand how ambient temperature and larval densities in the immature aquatic phases determine adult life history traits and dengue virus loads post-infection. We predicted that larval crowding and high temperatures would both lead to smaller mosquitoes that might struggle to invest in an immune response and, hence, would exhibit high viral loads. Methods. We first examined larval densities from urban and rural areas via a meta-analysis. We then used these data to inform a laboratory-based 2×2 design examining the interacting effects of temperature (21 vs. 26˚C) and density (0.2 vs. 0.4 larvae/mL) on adult life history and dengue virus loads. Results. We found that urban areas had an ~8-fold increase in larval densities compared to more rural sites. Crowding led to slower development, smaller mosquitoes, less survival, lower fecundity, and higher viral loads. The higher temperature led to faster development, reduced fecundity, and lower viral loads. The virus-reducing effect of higher temperature rearing was, however, overwhelmed by the impact of larval crowding when both factors were present. Conclusions. These data reveal complex interactions between the environmental effects experienced by immature mosquitoes and adult traits. They especially highlight the importance of crowding with respect to adult viral loads. Together, these data suggest that urban environments might enhance dengue virus loads and, therefore, possibly transmission, a concerning result given the increasing rates of urbanization globally.

F. Rubino and J. Foley Vector-Borne and Zoonotic Diseases Vol. 24, No. 11

https://doi.org/10.1089/vbz.2024.0012

Abstract Background: This study aimed to compare the exposure histories to ticks and tick-borne pathogens, knowledge, and prevention practices between individuals engaged in fire-related forest management and those participating in recreational activities within Santa Cruz County, CA, in an area of high risk of tick exposure. Methods: Blood samples from 55 forest workers and 58 members of the public were tested for bacterial DNA of and antibodies to Borrelia burgdorferi, Anaplasma phagocytophilum, and Rickettsia species. In addition, a questionnaire was administered to 54 workers and 84 members of the public to identify gaps in knowledge and prevention practices. Results: Although workers had a higher percentage of positive B. burgdorferi antibodies than the public (5.5% compared with 1.7%), the difference was not statistically significant. Conversely, rickettsial antibodies were more prevalent among the public (17.2% versus 3.6% for workers), but specificity to pathogenic bacteria could not be confirmed. No DNA for the three pathogens or antibodies against A. phagocytophilum were detected. Many workers and members of the public reported tick bites (67.4% of participants), with a notable 11% increase among workers in the odds of being bitten for each additional year spent working in forests. Although workers took greater precautions, significant knowledge and practice gaps were identified among both populations, such as an inability to distinguish tick species from common arthropods (mites, spiders, fleas), overestimating the size of ticks, and inappropriate tick-removal techniques. Conclusion: This study underscores the risk of tick-borne diseases faced by fire management workers in Lyme disease–endemic regions. The findings emphasize the necessity for future studies of Lyme disease within this population, and highlight the urgent need for enhanced training programs to minimize these risks.

Byers, NM, et al. Evidence of Limited Laboratory Infection of Culex Tarsalis (Diptera: Culicidae) by Usutu Virus. VECTOR-BORNE AND ZOONOTIC DISEASES Volume 00, Number 00, 2024. DOI: 10.1089/vbz.2024.0054

Abstract
Background: Usutu virus (USUV) is an emerging flavivirus, closely related to West Nile virus (WNV), that has spread into Europe from Africa. Since Culex tarsalis Coquillett is an important vector for WNV transmission in the United States, we tested the ability of USUV to replicate in and be transmitted by these mosquitoes. Materials and Methods: USUV was used to infect 3-4 day-old Cx. tarsalis with 5.6 to 7.5 log10 pfu/ml in goose bloodmeals. Saliva, heads, and bodies were collected on day 13 or 14 and analyzed by RT-qPCR for detection for USUV vRNA. Blotting paper punches were also collected daily to assess viral transmissibility. Results: The low and high dose blood meal resulted in 0% and 19.6% of the mosquitoes having established infections, respectively. All of the high dose had a dissemination of USUV RNA to the heads and none of the filter papers had detectable USUV RNA, but five of the capillary saliva collections were positive, representing 45.5% of the infected mosquitoes. Conclusions: Limited infection of Cx. tarsalis was observed when exposed to bloodmeals with greater than 10^7 pfu/mL of USUV, indicating this vector is not likely to have a key role in transmission of the virus.

Note: USUV is in the same Japanese encephalitis complex within the family Flaviviridae as WNV and SLEV. Cx. tarsalis is considered a potential vector of JEV based on vector competence studies [Reeves & Hammon. 1946. J. Exp. Med. 83: 185]. Because USUV causes extensive mortality in blackbirds, it is possible that mosquitoes could be exposed to higher blood meal titers in nature than used in these experiments. Also useful to remember that Cx. tarsalis is less suseptible to WNV than SLEV, and yet WNV is more prevalent because of its higher titers in infected avian hosts.

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A ProMED-mail post http://www.promedmail.org ProMED-mail is a program of the International Society for Infectious Diseases http://www.isid.org Date: Mon 7 Oct 2024 Source: PAHO/WHO Epidemiological Alert [edited] https://www.paho.org/en/documents/epidemiological-alert-increase-dengue-cases-americas-region-7-october-2024

Due to the increase in dengue cases reported by countries of the Central American Isthmus and Mexico during 2024 and considering the beginning of the dengue season in South America, the Pan American Health Organization/World Health Organization (PAHO/WHO) encourages Member States to continue their efforts in surveillance, early diagnosis, and timely care of dengue and other arbovirus cases, in order to prevent severe cases and deaths associated with these diseases, and, especially for countries in South America, to review their dengue response plans.

Summary of the situation in the Americas Region

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In the Americas Region, the number of dengue cases recorded during the first half of 2024 exceeded the number of cases historically reported in a year, as compared to all previously recorded years. As of epidemiological week (EW) 36 of 2024, 47 countries and territories in the Americas Region have reported 11 732 921 dengue cases; this number is 2.5 times as high as the number of cases recorded throughout 2023, which was 4 594 823 dengue cases (Figure 1 [for all figures, see source URL]) (1). Between EW 1 and EW 36 of 2024, of the total reported dengue cases, 6 253 754 (53%) were laboratory confirmed. Of this total, 17 610 were characterized as severe dengue (0.15%) and 6650 fatal cases were recorded (case fatality rate of 0.057%) (1). Cases from 6 countries make up 97% of the fatal dengue cases in the Americas Region: Brazil with 5303 (82.4%), Argentina with 408 (6.1%), Peru with 234 (3.5%), Colombia with 131 (1.97%), Paraguay with 121 (1.8%), and Ecuador with 59 (0.88%) fatal dengue cases (1). All 4 serotypes of the dengue virus have been circulating in the Americas Region as of EW 36 of 2024. Brazil, Costa Rica, El Salvador, Guatemala, Honduras, Mexico, and Panama report simultaneous circulation of the 4 serotypes (DENV-1, DENV-2, DENV-3, and DENV-4). Additionally, Argentina, French Guiana, Peru, and Puerto Rico reported simultaneous circulation of DENV-1, DENV-2, and DENV-3 (1). Note: The rest of the posting provides regional data for Mexico, Central and South American countries, all of which have marked increases in cases this year. The medical situation is complicated further by the circulation of all 4 strains of DENV which when contracted serially can lead to serious hemorrhagic disease complications.

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Date: Wed 2 Oct 2024

Source: Prensa Latina [in Spanish, machine trans., edited]

https://www.prensa-latina.cu/2024/10/02/alertan-en-panama-sobre-rebrote-epidemico-de-gusano-barrenador/

Panama warns of new outbreak of screwworm epidemic

————————————————–

Panamanian authorities have warned of a new epidemic the country is currently facing with cases of the cattle screwworm which also affects humans.

In statements to Prensa Latina, Carlos Moreno, from the Panama-United States Commission for the Eradication of the Screwworm (COPEG) specified the rise of the plague in mid-2023 was due to the lack of vigilance by both citizens and authorities during the COVID-19 pandemic.

In addition, he explained, the increase in cases, some 27 330 from 2022 to date, was due to other factors such as climate change, movement control, and greater awareness among the population.

The screwworm is not only affecting livestock; humans and other animal species are also being harmed.

In Panama, the Ministry of Health (MINSA) has recorded some 79 cases, according to epidemiologist Damaris Contreras, who called on people not to treat wounds at home but to go to health centers or hospitals.

The screwworm, which is laid by the fly _Cochliomyia hominivorax_, feeds on the living tissue of animals and can be fatal if not treated properly. This fly seeks to lay its eggs in “fresh wounds” of any type of warm-blooded animal. In a single wound, this fly can lay between 150 and 300 eggs, explained Lester Reyes, from Animal Health Epidemiology at the Ministry of Agricultural Development (MIDA). Once the larvae develop, they leave the wound and drop to the ground, where they bury themselves until they reach the pupal stage and thenbecome adult flies. Therefore, when healing these wounds, the maggots must be removed and eliminated immediately, because if they are left alive they turn into flies.

Panama has the only plant for the production of sterile flies which counteract the reproduction of flies laying the eggs of the screwworm. Specifically, the impact is occurring in other countries has led Panama to suspend the distribution of sterile flies, said Reynaldo Vivero, from MIDA, who also explained sterile flies are not being distributed in the country, since they are being sent to other countries to control the outbreak.

See attached for additional postings, comment and information.

—

Communicated by: ProMED

Note: The screwworm fly historically was endemic in the USA and was eradicated by the first SIT program. The fly eventually was pushed south of Mexico, with Panama being the southern border maintained by surveillance and further fly releases. Panama has the only remaining sterile fly production facility. The fly is still endemic in parts of South America. Northern dispersal, if not immediately contained, would require a large scale eradication effort that would be very costly.

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Date: Thu 3 Oct 2024

Source: KOST [edited] https://kost1035.iheart.com/featured/la-local-news/content/2024-10-03-5th-locally-acquired-dengue-case-confirmed-in-la-county/

Los Angeles County health officials Thursday [3 Oct 2024] continue to investigate a 5th locally acquired case of the mosquito-borne illness dengue, this time in a resident of El Monte. The latest patient does not appear to have any connection with the 4 previous reported infections, the county Department of Public Health said Wednesday [2 Oct 2024].

Health officials again stressed that locally acquired cases of dengue are extremely rare in areas where it has not been previously transmitted by mosquitoes. The county previously reported a cluster of 3 infections in the Baldwin Park area, and last week a 4th case was confirmed in a Panorama City resident. Health officials called the spate of local cases “unprecedented.”

None of the local patients had any history of travel to areas where dengue is endemic. In October and November of last year [2023], single locally acquired cases of dengue were confirmed by health officials in Pasadena and Long Beach.

Health officials noted that the symptoms of dengue often mirror those of other viruses, and they urged health-care providers to be “vigilant for dengue fever in patients with acute febrile illness and test for and report such cases of mosquito-borne diseases.”

— Communicated by: ProMED

FROM PROMED [It is interesting to note that the latest patient does not appear to have any connection with the 4 previous reported infections. There is a previously reported cluster of 3 cases in the Baldwin Park area, a single case in Panama City and now the latest one in El Monte. One wonders if there are several other dengue virus infected individuals in these 3 localities that have asymptomatic or very mild infections that have not resulted in medical attention so are not reported.

The above report does not indicate which vector mosquito was likely involved in dengue virus transmission in the 3 localities. As noted in the previously posted comment, the mosquitoes most likely involved are _Aedes aegypti_ or _Aedes albopictus_, both of which have been detected in California over the past 20 years. The preventive measures to avoid ongoing transmission are avoidance of mosquito bites and reduction of the mosquito populations. Mosquito control districts are undoubtedly attempting to control these vector mosquitoes, but that is a difficult task and requires collaboration with local residents to eliminate the water catchments in which these mosquitoes breed around their homes and other buildings.

Note that both _Aedes aegypti_ and _Aedes albopictus_ have been found in Los Angeles County. Which of these transmitted dengue virus to the residents is unknown. Locally acquired dengue virus infections remain extremely rare in California but occurrence of this cluster of cases indicates that local acquisition of dengue virus can occur. – Mod.TY

Note: The juxtaposition of these cases to the primary or imported cases has not been reported. As indicated above, it would seem that potentially other perhaps milder secondary cases have gone unnoticed, although these could still be a source of virus for mosquito infection making a vector control response difficult to focus geographically.